Fibrous Structures and Methods for Making Same

ABSTRACT

Fibrous structures, more particularly wet-laid fibrous structures that exhibit one or more of the following characteristics: a wet-formed surface pattern that includes large cells, for example that exhibits a cell count of less than 120 cells/in1 and/or that is visually discernible to the naked eye dry and wet and/or is felt by users dry and wet and/or exhibits sufficient flexural rigidity and/or plate stiffness to feel more like a cloth than known wet-laid fibrous structures and/or feels less wet (dry-to-the-touch) after wetting than known wet-laid fibrous structures and methods for making same are provided.

FIELD OF THE INVENTION

The present invention relates to fibrous structures, more particularly to wet-laid fibrous structures that exhibit one or more of the following characteristics: a wet-formed surface pattern that comprises large cells, for example that exhibits a cell count of less than 120 cells/in² and/or that is visually discernible to the naked eye dry and wet and/or is felt by users dry and wet and/or exhibits sufficient flexural rigidity and/or plate stiffness to feel more like a cloth than known wet-laid fibrous structures and/or feels less wet (dry-to-the-touch) after wetting than known wet-laid fibrous structures and methods for making same.

BACKGROUND OF THE INVENTION

A key drive for value in fibrous structures, for example paper towels, is life-in-sheet, in other words, does the paper towel feel like it still has use left in it after wetting it. One way that users of paper towels derive their impression of life-in-sheet and/or value is how the paper towel reacts and feels after wetting. Does the paper towel go limp after wetting? Does the paper towel feel like a wet noodle after wetting? Does any texture, such as a surface pattern, which may be visually discernible when dry and actually may be one factor in the user purchasing the towel in the first place, become invisible or less visually discernible after wetting the paper towel? Does the paper towel reopen, for example spring back open or at least does not inhibit reopening after wetting? Does the paper towel exhibit cloth-like properties before and/or especially after wetting, such as drape as evidenced by for example flexural rigidity and/or plate stiffness, and softness and/or surface of paper towel feeling less wet that known paper towels?

Known fibrous structures, for example known wet-laid sanitary tissue products, such as known wet-laid paper towels, do not exhibit sufficient life-in-sheet properties/characteristics set forth in the immediate paragraph above, especially when trying to balance the dry and wet feel of the paper towel.

Known fibrous structures, for example known wet-laid sanitary tissue products, such as known wet-laid paper towels do comprise surfaces that exhibit texture, typically imparted to the surfaces by an embossing operation and/or imparted to the surfaces by a molding operation, for example wet-formed/wet-molding operation utilizing a molding member. Known emboss patterns on wet-laid fibrous structures, such as wet-laid sanitary tissue products, especially wet-laid paper towels tend to be very visually impactful and discernible, however, such embossing patterns disappear when wetted due to the fact that the embossing patterns are deformations formed in the surface of the wet-laid fibrous structures when the wet-laid fibrous structures are dry, in other words, the embossing patterns are not wet-formed patterns made during papermaking. On the other hand, wet-formed/wet-molded surface patterns on surfaces of wet-laid fibrous structures, for example wet-laid sanitary tissue product, especially wet-laid paper towels are formed wet during papermaking operations by rearranging fibers into a surface pattern of a molding member prior to drying of the wet-laid fibrous structure. Therefore, these known wet-formed/wet-molded surface patterns to remain when wet, but the problem is that these known wet-formed/wet-molded patterns comprise small cells, for example cells that exhibit a cell count much greater than 150 cells/in², for example over 500 cells/in² that result in the cells and the surface pattern made therefrom being not visually discernible when the wet-laid fibrous structure is dry or wet, especially when wet.

In the past, large cell patterns, for example cell counts less than 150 cells/in² and/or less than 120 cells/in², for example discrete pillow patterns that have had cell counts less than 150 cells/in² and/or less than 120 cells/in² have not been able to be made successfully without negatives. For example, such known large cell patterns comprising discrete pillows have resulted in shrinking and/or curling of the wet-laid fibrous structures during the making process.

In addition, large cell patterns, for example cell counts less than 150 cells/in² and/or less than 120 cells/in², for example discrete knuckle patterns that have had cell counts less than 150 cells/in² and/or less than 120 cells/in², such as a discrete knuckle pattern having a cell count of 95 cells/in² have not been able to be made successfully without negatives. For example, such known large cell patterns comprising discrete knuckles have resulted in drying issues with the wet-laid fibrous structure during the making process. shrinking and/or curling of the wet-laid fibrous structures.

There is a need for a fibrous structure, for example a wet-laid fibrous structure, such as a wet-laid sanitary tissue product, especially a wet-laid paper towel that overcomes the negatives described above.

SUMMARY OF THE INVENTION

The present invention fulfills the needs described above by providing a fibrous structure, for example a wet-laid fibrous structure, such as a wet-laid sanitary tissue product, for example a wet-laid paper towel exhibits one or more of the following characteristics: a wet-formed surface pattern that comprises large cells, for example that exhibits a cell count of less than 120 cells/in² and/or that is visually discernible to the naked eye dry and wet and/or is felt by users dry and wet and/or exhibits sufficient flexural rigidity and/or plate stiffness to feel more like a cloth than known wet-laid fibrous structures and/or feels less wet, for example feels dry-to-the-touch, after wetting than known wet-laid fibrous structures and/or exhibits enhanced re-openability and/or maintains its shape after wetting and wringing out and methods for making same.

In one example of the present invention, a compacted fibrous structure article as set forth herein and in the claims is provided.

In one example of the present invention, a fibrous structure comprising a surface comprising a plurality of first pillows wherein at least a portion of the plurality of first pillows are at least partially, for example fully, bounded by at least a portion of a second pillow different from the plurality of first pillows, wherein the portion of the second pillow exhibits a maximum width that is less than the maximum dimension of one or more of the plurality of first pillows, is provided.

In another example of the present invention, a dry-to-the-touch (after wetting, for example after absorbing up to and/or a portion of its absorbent capacity) fibrous structure comprising a surface comprising a plurality of first pillows wherein at least a portion of the plurality of first pillows are at least partially, for example fully, bounded by at least a portion of a second pillow different from the plurality of first pillows, wherein the portion of the second pillow exhibits a maximum width that is less than the maximum dimension of one or more of the plurality of first pillows, is provided.

In still another example of the present invention, a fibrous structure comprising a surface comprise a plurality of first pillows that exhibit a cell count of at least 120/in², wherein the fibrous structure comprises a plurality of non-thermoplastic fibers, is provided.

In even another example of the present invention, a fibrous structure comprising a surface comprise a plurality of first pillows that exhibit a cell count of at least 120 cells/in², wherein the fibrous structure comprises a plurality of water-insensitive fibers, is provided.

In yet another example of the present invention, a process for making a fibrous structure, the process comprising the step of using a molding member of the present invention to form a fibrous structure of the present invention, is provided.

The present invention provides novel fibrous structures and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an example of a molding member suitable for use in making a fibrous structure for use in a fibrous structure according to the present invention;

FIG. 1B is another example of a molding member suitable for use in making a fibrous structure for use in a fibrous structure according to the present invention;

FIG. 1C are scanning electron microscope (SEM) images of examples of surfaces of fibrous structures according to the present invention;

FIG. 2A are μCT images of examples of multi-ply fibrous structures according to the present invention;

FIG. 2B are μCT images of examples of multi-ply fibrous structures according to the present invention;

FIG. 3 are SEM images of examples of surfaces of examples of fibrous structures according to the present invention;

FIG. 4 is an SEM image of an example of a surface an example of fibrous structures according to the present invention;

FIG. 5 is a schematic representation of an example of a Prior Art Molding Member;

FIG. 6 is a schematic representation of another example of a Prior Art Molding Member;

FIG. 7 is a schematic representation of another example of a Prior Art Molding Member;

FIG. 8 is a schematic representation of a process for making a fibrous structure according to the present invention;

FIG. 9 is a graph of Moist Contact Area (%) to Moist—10 Low Median Depth (Moist Depth) (μm) of inventive fibrous structures and prior art fibrous structures;

FIG. 10 is a schematic representation of a Capacity Rate Tester set-up for use with the SST Absorbency Rate Test Method described herein;

FIG. 11 is a schematic representation of a set-up for use with the Moist Towel Surface Structure Test Method described herein;

FIG. 12 is a schematic top view representation of a Slip Stick Coefficient of Friction Test Method set-up;

FIG. 13 is an image of a friction sled for use in the Slip Stick Coefficient of Friction Test Method; and

FIG. 14 is a schematic side view representation of a Slip Stick Coefficient of Friction Test Method set-up.

DETAILED DESCRIPTION OF THE INVENTION

“Sanitary tissue product” as used herein means a soft, low density (i.e. <about 0.15 g/cm³) article comprising one or more fibrous structure plies according to the present invention, wherein the sanitary tissue product is useful as a wiping implement for post-urinary and post-bowel movement cleaning (toilet tissue), for otorhinolaryngological discharges (facial tissue), and multi-functional absorbent and cleaning uses (absorbent towels). The sanitary tissue product may be convolutedly wound upon itself about a core or without a core to form a sanitary tissue product roll.

The sanitary tissue products and/or fibrous structures of the present invention may exhibit a basis weight of greater than 15 g/m² to about 120 g/m² and/or from about 15 g/m² to about 110 g/m² and/or from about 20 g/m² to about 100 g/m² and/or from about 30 to 90 g/m². In addition, the sanitary tissue products and/or fibrous structures of the present invention may exhibit a basis weight between about 40 g/m² to about 120 g/m² and/or from about 50 g/m² to about 110 g/m² and/or from about 55 g/m² to about 105 g/m² and/or from about 60 to 100 g/m².

The sanitary tissue products of the present invention may exhibit a sum of MD and CD dry tensile strength (total dry tensile) of greater than about 59 g/cm (150 g/in) and/or from about 78 g/cm to about 394 g/cm and/or from about 98 g/cm to about 335 g/cm. In addition, the sanitary tissue product of the present invention may exhibit a sum of MD and CD dry tensile strength of greater than about 196 g/cm and/or from about 196 g/cm to about 394 g/cm and/or from about 216 g/cm to about 335 g/cm and/or from about 236 g/cm to about 315 g/cm. In one example, the sanitary tissue product exhibits a sum of MD and CD dry tensile strength of less than about 394 g/cm and/or less than about 335 g/cm.

In another example, the sanitary tissue products of the present invention may exhibit a sum of MD and CD dry tensile strength (total dry tensile) of greater than about 196 g/cm and/or greater than about 236 g/cm and/or greater than about 276 g/cm and/or greater than about 315 g/cm and/or greater than about 354 g/cm and/or greater than about 394 g/cm and/or from about 315 g/cm to about 3200 g/cm and/or from about 315 g/cm to about 2700 g/cm and/or from about 325 g/cm to about 2000 g/cm and/or from about 354 g/cm to about 1181 g/cm and/or from about 354 g/cm to about 984 g/cm and/or from about 394 g/cm to about 787 g/cm. In one example, the sanitary tissue products of the present invention exhibit a total dry tensile of from about 1500 g/cm to about 2500 g/cm.

The sanitary tissue products of the present invention may exhibit an initial sum of MD and CD wet tensile strength (initial total wet tensile) of less than about 78 g/cm and/or less than about 59 g/cm and/or less than about 39 g/cm and/or less than about 29 g/cm.

The sanitary tissue products of the present invention may exhibit an initial sum of MD and CD wet tensile strength (initial total wet tensile) of greater than about 118 g/cm and/or greater than about 157 g/cm and/or greater than about 196 g/cm and/or greater than about 236 g/cm and/or greater than about 276 g/cm and/or greater than about 315 g/cm and/or greater than about 354 g/cm and/or greater than about 394 g/cm and/or from about 118 g/cm to about 1968 g/cm and/or from about 157 g/cm to about 1181 g/cm and/or from about 196 g/cm to about 984 g/cm and/or from about 196 g/cm to about 787 g/cm and/or from about 196 g/cm to about 591 g/cm.

The sanitary tissue products of the present invention may exhibit a density (based on measuring caliper at 95 g/in²) of less than about 0.60 g/cm³ and/or less than about 0.30 g/cm³ and/or less than about 0.20 g/cm³ and/or less than about 0.10 g/cm³ and/or less than about 0.07 g/cm³ and/or less than about 0.05 g/cm³ and/or from about 0.01 g/cm³ to about 0.20 g/cm³ and/or from about 0.02 g/cm³ to about 0.10 g/cm³.

The sanitary tissue product may comprise a plurality of connected, but perforated sheets of fibrous structure, that are separably dispensable from adjacent sheets.

The fibrous structures and/or sanitary tissue products of the present invention may comprise additives such as cleaning compositions, for example cleaning compositions comprising surfactants, such as lathering surfactants and/or foaming surfactants, surface softening agents, for example silicones, quaternary ammonium compounds, aminosilicones, lotions, and mixtures thereof, temporary wet strength agents, permanent wet strength agents, bulk softening agents, wetting agents, latexes, especially surface-pattern-applied latexes, dry strength agents such as carboxymethylcellulose and starch, and other types of additives suitable for inclusion in and/or on sanitary tissue products.

In one example, the sanitary tissue product and/or fibrous structure of the present invention exhibits permanent wet strength and/or comprises permanent wet strength agents. In another example, the sanitary tissue product and/or fibrous structure of the present invention comprises a temporary wet strength agent and/or is void of permanent wet strength. In one example, the sanitary tissue product and/or fibrous structure of the present invention if flushable, for example flushable via toilets into municipal sewer systems and/or septic systems, for example bath tissue void of permanent wet strength. In another example, the sanitary tissue product and/or fibrous structure article is not suitable for flushing, for example not suitable for flushing via toilets into municipal sewer systems and/or septic systems, for example paper towels and/or facial tissues exhibiting permanent wet strength.

“Fibrous structure” as used herein means a structure that comprises a plurality of fibrous elements, for example a plurality of filaments and/or fibers, such as a plurality of pulp fibers, for example wood pulp fibers. In one example, the fibrous structure may comprise a plurality of wood pulp fibers. In another example, the fibrous structure may comprise a plurality of non-wood pulp fibers, for example plant fibers, synthetic staple fibers, and mixtures thereof. In still another example, in addition to or alternative to fibers, such as pulp fibers, the fibrous structure may comprise a plurality of filaments, such as polymeric filaments, for example thermoplastic filaments such as polyolefin filaments (i.e., polypropylene filaments), such as in the form of a co-formed fibrous structure where the pulp fibers and filaments are commingled together. In one example, a fibrous structure according to the present invention means an orderly arrangement of fibrous elements, for example filaments or fibers alone or in combination with each other within a structure in order to perform a function. Non-limiting examples of fibrous structures of the present invention include paper, such as wet-laid fibrous structures, for example wet-laid paper.

Non-limiting examples of processes for making fibrous structures include known wet-laid papermaking processes, for example conventional wet-pressed papermaking processes and through-air-dried papermaking processes, and air-laid papermaking processes. Such processes typically include steps of preparing a fiber composition in the form of a suspension in a medium, either wet, more specifically aqueous medium, or dry, more specifically gaseous, i.e. with air as medium. The aqueous medium used for wet-laid processes is oftentimes referred to as a fiber slurry. The fibrous slurry is then used to deposit a plurality of fibers onto a forming wire, fabric, or belt such that an embryonic fibrous structure is formed, after which drying and/or bonding the fibers together results in a fibrous structure. Further processing the fibrous structure may be carried out such that a finished fibrous structure is formed. For example, in typical papermaking processes, the finished fibrous structure is the fibrous structure that is wound on the reel at the end of papermaking, often referred to as a parent roll, and may subsequently be converted into a finished product, e.g. a single- or multi-ply sanitary tissue product.

In one example, the fibrous structure and/or sanitary tissue product is a non-hydroentangled fibrous structure and/or sanitary tissue product.

In another example, the fibrous structure and/or sanitary tissue product is a hydroentangled fibrous structure and/or sanitary tissue product.

In one example, the fibrous structure and/or sanitary tissue product is a non-carded fibrous structure and/or sanitary tissue product.

In still another example, the fibrous structure and/or sanitary tissue product is a carded-fibrous structure.

Other non-limiting examples of processes for making example of fibrous structure according to the present invention include meltblowing processes, for example using a meltblow die, such as a knife-edge die and/or a multi-row capillary meltblow die, for example a Biax-Fiberfilm Corporation multi-row capillary meltblow die. In one example, the fibrous structure is a meltblow fibrous structure produced from a meltblow die, for example a multi-row capillary meltblow die. In another example, the fibrous structure is a co-formed fibrous structure produced by commingling a plurality of filaments produced from a multi-row capillary meltblow die with a plurality of solid additives, such as fibers, for example pulp fibers, such as wood pulp fibers and optionally an included scrim on at least one surface of the co-formed fibrous structure, wherein the scrim is produced by spinning a plurality of filaments from a meltblow die, for example a multi-row meltblow die, and collecting the spun filament directly on a surface of the co-formed fibrous structure. In addition to meltblowing processes, the fibrous structure of the present invention may be produced from a spunbonding process. In one example, the fibrous structure is a spunbond fibrous structure produced form a spunbond die. In another example, the fibrous structure comprises one or more meltblow fibrous structures and/or meltblow layers and one or more spunbond fibrous structures and/or spunbond layers and/or one or more pulp fiber fibrous structures and/or pulp fiber layers.

The fibrous structures of the present invention may be homogeneous or may be layered. If layered, the fibrous structures may comprise at least two and/or at least three and/or at least four and/or at least five layers of fiber and/or filament compositions.

In one example, the fibrous structure of the present invention consists essentially of fibers, for example pulp fibers, such as cellulosic pulp fibers and more particularly wood pulp fibers.

In another example, the fibrous structure of the present invention comprises fibers and is void of filaments.

“Co-formed fibrous structure” as used herein means that the fibrous structure comprises a mixture of at least two different materials wherein at least one of the materials comprises a filament, such as a polypropylene filament, and at least one other material, different from the first material, comprises a solid additive, such as a fiber and/or a particulate. In one example, a co-formed fibrous structure comprises solid additives, such as fibers, such as wood pulp fibers, and filaments, such as polypropylene filaments.

“Fibrous element” and/or “Fiber” and/or “Filament” as used herein means an elongate particulate having an apparent length greatly exceeding its apparent width, i.e. a length to diameter ratio of at least about 10. In one example, a “fiber” is an elongate particulate as described above that exhibits a length of less than 5.08 cm (2 in.) and a “filament” is an elongate particulate as described above that exhibits a length of greater than or equal to 5.08 cm (2 in.).

Fibers are typically considered discontinuous in nature. Non-limiting examples of fibers include pulp fibers, such as wood pulp fibers, and synthetic staple fibers such as polyester fibers.

Filaments are typically considered continuous or substantially continuous in nature. Filaments are relatively longer than fibers. Non-limiting examples of filaments include meltblown and/or spunbond filaments. Non-limiting examples of materials that can be spun into filaments include synthetic polymers including, but not limited to thermoplastic polymer filaments, such as polyesters, nylons, polyolefins such as polypropylene filaments, polyethylene filaments, and biodegradable or compostable thermoplastic fibers such as polylactic acid filaments, polyhydroxyalkanoate filaments, polyesteramide filaments, and polycaprolactone filaments. The filaments may be monocomponent or multicomponent, such as bicomponent filaments.

In one example of the present invention, “fiber” refers to papermaking fibers. Papermaking fibers useful in the present invention include cellulosic fibers commonly known as wood pulp fibers. Applicable wood pulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps, as well as mechanical pulps including, for example, groundwood, thermomechanical pulp and chemically modified thermomechanical pulp. Chemical pulps, however, may be preferred since they impart a superior tactile sense of softness to tissue sheets made therefrom. Pulps derived from both deciduous trees (hereinafter, also referred to as “hardwood”) and coniferous trees (hereinafter, also referred to as “softwood”) may be utilized. The hardwood and softwood fibers can be blended, or alternatively, can be deposited in layers to provide a stratified fibrous structure. U.S. Pat. Nos. 4,300,981 and 3,994,771 are incorporated herein by reference for the purpose of disclosing layering of hardwood and softwood fibers. Also applicable to the present invention are fibers derived from recycled paper, which may contain any or all of the above categories as well as other non-fibrous materials such as fillers and adhesives used to facilitate the original papermaking.

In one example, the wood pulp fibers are selected from the group consisting of hardwood pulp fibers, softwood pulp fibers, and mixtures thereof. The hardwood pulp fibers may be selected from the group consisting of: tropical hardwood pulp fibers, northern hardwood pulp fibers, and mixtures thereof. The tropical hardwood pulp fibers may be selected from the group consisting of: eucalyptus fibers, acacia fibers, and mixtures thereof. The northern hardwood pulp fibers may be selected from the group consisting of: cedar fibers, maple fibers, and mixtures thereof.

In addition to the various wood pulp fibers, other cellulosic fibers such as cotton linters, rayon, lyocell, trichomes, seed hairs, and bagasse can be used in this invention. Other sources of cellulose in the form of fibers or capable of being spun into fibers include grasses and grain sources.

“Trichome” or “trichome fiber” as used herein means an epidermal attachment of a varying shape, structure and/or function of a non-seed portion of a plant. In one example, a trichome is an outgrowth of the epidermis of a non-seed portion of a plant. The outgrowth may extend from an epidermal cell. In one embodiment, the outgrowth is a trichome fiber. The outgrowth may be a hairlike or bristlelike outgrowth from the epidermis of a plant.

Trichome fibers are different from seed hair fibers in that they are not attached to seed portions of a plant. For example, trichome fibers, unlike seed hair fibers, are not attached to a seed or a seed pod epidermis. Cotton, kapok, milkweed, and coconut coir are non-limiting examples of seed hair fibers.

Further, trichome fibers are different from non-wood bast and/or core fibers in that they are not attached to the bast, also known as phloem, or the core, also known as xylem portions of a non-wood dicotyledonous plant stem. Non-limiting examples of plants which have been used to yield non-wood bast fibers and/or non-wood core fibers include kenaf, jute, flax, ramie and hemp.

Further trichome fibers are different from monocotyledonous plant derived fibers such as those derived from cereal straws (wheat, rye, barley, oat, etc.), stalks (corn, cotton, sorghum, Hesperaloe funifera, etc.), canes (bamboo, bagasse, etc.), grasses (esparto, lemon, sabai, switchgrass, etc), since such monocotyledonous plant derived fibers are not attached to an epidermis of a plant.

Further, trichome fibers are different from leaf fibers in that they do not originate from within the leaf structure. Sisal and abaca are sometimes liberated as leaf fibers.

Finally, trichome fibers are different from wood pulp fibers since wood pulp fibers are not outgrowths from the epidermis of a plant; namely, a tree. Wood pulp fibers rather originate from the secondary xylem portion of the tree stem.

In one example, the fibers may comprise monocotyledonous plant derived fibers such as those derived from cereal straws (wheat, rye, barley, oat, etc), stalks (corn, cotton, sorghum, Hesperaloe funifera, etc.), canes (bamboo, bagasse, etc.), grasses (esparto, lemon, sabai, switchgrass, etc) and mixtures thereof.

“Basis Weight” as used herein is the weight per unit area of a sample reported in lbs/3000 ft² or g/m² (gsm) and is measured according to the Basis Weight Test Method described herein.

“Machine Direction” or “MD” as used herein means the direction parallel to the flow of the fibrous structure through the fibrous structure making machine and/or sanitary tissue product manufacturing equipment.

“Cross Machine Direction” or “CD” as used herein means the direction parallel to the width of the fibrous structure making machine and/or sanitary tissue product manufacturing equipment and perpendicular to the machine direction.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrous structures disposed in a substantially contiguous, face-to-face relationship with one another, forming a multi-ply fibrous structure and/or multi-ply sanitary tissue product. It is also contemplated that an individual, integral fibrous structure can effectively form a multi-ply fibrous structure, for example, by being folded on itself.

“Embossed” as used herein with respect to a fibrous structure and/or sanitary tissue product means that a fibrous structure and/or sanitary tissue product has been subjected to a process which converts a smooth surfaced fibrous structure and/or sanitary tissue product to a decorative surface by replicating a design on one or more emboss rolls, which form a nip through which the fibrous structure and/or sanitary tissue product passes. Embossed does not include creping, microcreping, printing or other processes that may also impart a texture and/or decorative pattern to a fibrous structure and/or sanitary tissue product.

“Differential density”, as used herein, means a fibrous structure and/or sanitary tissue product comprises one or more regions of relatively low fibrous element density, which are referred to as pillow regions, and one or more regions of relatively high fibrous element density, which are referred to as knuckle regions. In one example of the present invention, a fibrous structure and/or sanitary tissue product of the present invention comprises a surface comprising a surface pattern comprising a continuous pillow region, such as a continuous pillow network, one or more discrete knuckle regions, such as a discrete, continuous knuckle network dispersed throughout the continuous pillow network, and a one or more discrete pillow regions, such as a plurality of discrete pillows dispersed throughout the discrete, continuous knuckle network, which in turn is dispersed throughout the continuous pillow network.

“Densified”, as used herein means a portion of a fibrous structure and/or sanitary tissue product that is characterized by regions of relatively high fibrous element density (for example knuckle regions within a fibrous structure and/or sanitary tissue product).

“Non-densified”, as used herein, means a portion of a fibrous structure and/or sanitary tissue product that exhibits a lesser density (one or more regions of relatively lower fiber density) (for example a pillow region within a fibrous structure and/or sanitary tissue product) than another portion (for example a knuckle region within a fibrous structure and/or sanitary tissue product) of the fibrous structure and/or sanitary tissue product.

“Creped” as used herein means creped off of a Yankee dryer or other similar roll and/or fabric creped and/or belt creped. Rush transfer of a fibrous structure alone does not result in a “creped” fibrous structure or “creped” sanitary tissue product for purposes of the present invention.

“Juxtaposed” as used herein means two or more groups (for example two or more discrete pillow regions) are arranged side-by-side for contrasting effect.

“Repeat unit” as used herein means a pattern unit, which is the part or section of a pattern that is repeated to create the pattern, such as the surface pattern of a fibrous structure according to the present invention. In one example, the repeat unit is defined by and/or formed by and/or consists of a group of two or more and/or three or more discrete pillow regions. In another example, the repeat unit is defined by and/or formed by and/or consists of two or more groups of two or more and/or three or more discrete pillow regions. In one example, a repeat unit of the present invention comprises a portion of a surface pattern that comprises a discrete, continuous knuckle region, for example a discrete, continuous knuckle network that contains within it to or more discrete pillow regions.

In one example, a repeat unit, for example a group of two or more and/or three or more discrete pillow regions is translated and/or rotated and/or reflected to form a surface pattern on a fibrous structure from the repeat unit.

In another example, a repeat unit, for example a group of two or more and/or three or more discrete pillow regions is translated and rotated to form a surface pattern on a fibrous structure from the repeat unit.

In one example, a repeat unit, for example two groups of two or more and/or three or more discrete pillow regions is translated and/or rotated and/or reflected to form a surface pattern on a fibrous structure from the repeat unit.

In another example, a repeat unit, for example two groups of two or more and/or three or more discrete pillow regions is translated and rotated to form a surface pattern on a fibrous structure from the repeat unit.

In one example, the wet-laid papermaking process can be designed such that the fibrous structure has visually distinct features “wet-formed” during the papermaking process. Any of the various forming wires and papermaking belts utilized can be designed to leave physical, three-dimensional features within the fibrous structure. Such three-dimensional features are well known in the art, particularly in the art of “through air drying” (TAD) papermaking processes, with such features often being referred to in terms of “knuckles” and “pillows.” “Knuckles,” or “knuckle regions,” are typically relatively high-density regions that are wet-formed within the fibrous structure (extending from a pillow surface of the fibrous structure) and correspond to the knuckles of a papermaking belt, i.e., the filaments or resinous structures that are raised at a higher elevation than other portions of the belt. “Relatively high density” as used herein means a portion of a fibrous structure having a density that is higher than a relatively low-density portion of the fibrous structure. Relatively high density can be in the range of 0.1 to 0.13 g/cm³, for example, relative to a low density that can be in the range of 0.02 g/cm³ to 0.09 g/cm³.

Likewise, “pillows,” or “pillow regions,” are typically relatively low-density regions that are wet-formed within the fibrous structure and correspond to the relatively open regions between or around the knuckles of the papermaking belt. The pillow regions form a pillow surface of the fibrous structure from which the knuckle regions extend. “Relatively low density” as used herein means a portion of a fibrous structure having a density that is lower than a relatively high-density portion of the fibrous structure. Relatively low density can be in the range of 0.02 g/cm³ to 0.09 g/cm³, for example relative to a high density that can be in the range of 0.1 to 0.13 g/cm³. Further, the knuckles and pillows wet-formed within a fibrous structure can exhibit a range of basis weights and/or densities relative to one another, as varying the size of the knuckles or pillows on a papermaking belt can alter such basis weights and/or densities. A fibrous structure (e.g., sanitary tissue products) made through a TAD papermaking process as detailed herein is known in the art as “TAD paper.”

Thus, in the description herein, the terms “knuckles” or “knuckle regions,” or the like can be used to reference either the raised portions of a papermaking belt or the densified, raised portions wet-formed within the fibrous structure made on the papermaking belt (i.e., the raised portions that extend from a surface of the fibrous structure), and the meaning should be clear from the context of the description herein. Likewise “pillows” or “pillow regions” or the like can be used to reference either the portion of the papermaking belt between or around knuckles (also referred to herein and in the art as “deflection conduits” or “pockets”), or the relatively uncompressed regions wet-formed between or around the knuckles within the fibrous structure made on the papermaking belt, and the meaning should be clear from the context of the description herein. Knuckles and pillows and/or molding members used to impart the knuckles (resin feature(s) on molding member) and pillows (deflection conduit(s) on molding member) and may each be either continuous or discrete and/or may be a discrete, continuous network dispersed in a continuous network and/or may be discrete dispersed in a discrete, continuous network, which itself is dispersed in a continuous network as shown in shown in FIGS. 1A-1C.

The fibrous structures illustrated herein either exhibit a structure of discrete pillows and a continuous/substantially continuous knuckle region, or a structure of discrete knuckles and a continuous/substantially continuous pillow region. However, for every example described or illustrated herein, the inverse of such structure is also contemplated. In other words, if a structure of discrete knuckles and a continuous/substantially continuous pillow region is shown, an inverse similar structure of continuous/substantially continuous knuckles and discrete pillows is also contemplated. Moreover, in regard to the papermaking belts, as can be understood by the description herein, the inverse relationship can be achieved by inverting the black and white (or, more generally, the opaque and transparent) portions of the mask used to make the belt that is used to make the fibrous structure. This inverse relation (black/white) can apply to all patterns of the present disclosure, although all fibrous structures/patterns of each category are not illustrated for brevity. The papermaking belts (molding members) of the present disclosure and the process of making them are described in further detail below.

Fibrous Structures/Sanitary Tissue Products

The fibrous structures and/or sanitary tissue products of the present invention may be single-ply or multi-ply sanitary tissue products. In other words, the sanitary tissue products of the present invention may comprise one or more fibrous structures. The fibrous structures and/or sanitary tissue products of the present invention are made from a plurality of pulp fibers, for example wood pulp fibers and/or other cellulosic pulp fibers, for example trichomes. In addition to the pulp fibers, the fibrous structures and/or sanitary tissue products of the present invention may comprise synthetic fibers and/or filaments.

In one example, the surface pattern of the fibrous structure may comprise at least two of the discrete pillow regions within a group that are the same in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise all of the discrete pillow regions within a group that are the same in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise at least two of the discrete pillow regions within at least two groups that are the same in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise all of the discrete pillow regions within at least two groups that are the same in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise at least two of the discrete pillow regions that are different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise a plurality of the discrete pillow regions that are different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise at least two of the discrete pillow regions within a group that are different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise all of the discrete pillow regions within a group that are the different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise at least two of the discrete pillow regions within at least two groups that are different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the surface pattern of the fibrous structure may comprise all of the discrete pillow regions within at least two groups that are different in one or more dimensions/properties/characteristics of discrete pillows and/or discrete pillow regions, for example length, width, shape, orientation, etc.

In one example, the fibrous structures of the present invention comprise a plurality of fibers, for example pulp fibers, such as wood pulp fibers and/or non-wood pulp fibers.

In one example, the fibrous structures of the present invention may comprise a structured fibrous structure, for example a through-air-dried fibrous structure ply, such as a creped through-air-dried fibrous structure ply and/or an uncreped through-air-dried fibrous structure ply. Other non-limiting examples of structured fibrous structures include fabric creped fibrous structure plies, belt creped fibrous structure plies, ATMOS fibrous structure plies, NTT fibrous structure plies, ETAD fibrous structure plies, QRT fibrous structure plies, and STT fibrous structure plies.

In one example, the fibrous structures of the present invention may comprise a surface pattern that comprises a regular pattern and/or a non-random, repeating pattern and/or a molded microscopical three-dimensional pattern.

Dimensions of discrete pillow regions of the present invention are related to the dimensions of the discrete pillows within the molding members since the discrete pillows impart the discrete pillow regions to the fibrous structures of the present invention.

In one example, the fibrous structures of the present invention may comprise a surface pattern that is wet-formed, for example during the papermaking process for making the fibrous structure.

The fibrous structures of the present invention may be employed as a fibrous structure ply or fibrous structure plies in single- and/or multi-ply sanitary tissue products, for example single- or multi-ply sanitary tissue products with one or more other fibrous structure plies.

The fibrous structures and/or sanitary tissue products of the present invention may exhibit an average TS7 value of less than 10 and/or less than 9 and/or less than 8 and/or less than 7 and/or less than 6 and/or less than 5.5 and/or greater than 4 and/or greater than 4.5 and/or greater than 5 dB V² rms as measured according to the Emtec Test Method described herein.

The fibrous structures and/or sanitary tissue products of the present invention may be creped or uncreped.

The fibrous structures and/or sanitary tissue products of the present invention may be wet-laid or air-laid.

The fibrous structures and/or sanitary tissue products of the present invention may be embossed.

The fibrous structures and/or sanitary tissue products of the present invention may comprise a surface softening agent or be void of a surface softening agent. In one example, the sanitary tissue product is a non-lotioned sanitary tissue product, such as a sanitary tissue product comprising a non-lotioned fibrous structure ply, for example a non-lotioned through-air-dried fibrous structure ply, for example a non-lotioned creped through-air-dried fibrous structure ply and/or a non-lotioned uncreped through-air-dried fibrous structure ply. In yet another example, the sanitary tissue product may comprise a non-lotioned fabric creped fibrous structure ply and/or a non-lotioned belt creped fibrous structure ply.

The fibrous structures and/or sanitary tissue products of the present invention may comprise trichome fibers and/or may be void of trichome fibers.

In one example, the fibrous structure of the present invention, for example a paper towel, may comprise a series of line embossments 32 and dot embossments 34 in combination with a knuckle and pillow molded microscopical three-dimensional pattern.

In one example, the fibrous structures and/or sanitary tissue products of the present invention may exhibit the following properties:

A basis weight of between about 30 g/m² and about 80 g/m², or between about 40 g/m² and about 65 g/m², or between about 45 g/m² and about 60 g/m², or between about 50 g/m² and about 58 g/m², or between about 50 g/m² and about 55 g/m² as measured according to the Basis Weight Test Method described herein.

An Emtec TS7 value of less than about 20.00 dB V² rms, or less than about 19.50 dB V² rms, or less than about 19.00 dB V² rms, or less than about 18.50 dB V² rms, or less than about 18.00 dB V² rms, or less than about 17.50 dB V² rms, or between about 0.01 dB V² rms and about 20.00 dB V² rms, or between about 0.01 dB V² rms and about 19.50 dB V² rms, or between about 0.01 dB V² rms and about 19.00 dB V² rms, or between about 0.01 dB V² rms and about 18.50 dB V² rms, or between about 0.01 dB V² rms and about 18.00 dB V² rms, or between about 0.01 dB V² rms and about 17.50 dB V² rms, or between about 5.0 dB V² rms and about 20.00 dB V² rms, or between about 10.00 dB V² rms and about 20.00 dB V² rms, or between about 15.00 dB V² rms and about 20.00 dB V² rms as measured according to the Emtec Test Method described herein.

An SST value (absorbency rate) of greater than about 1.60 g/sec^(0.5), or greater than about 1.65 g/sec^(0.5), or greater than about 1.70 g/sec^(0.5), or greater than about 1.75 g/sec^(0.5), or greater than about 1.80 g/sec^(0.5), or greater than about 1.82 g/sec^(0.5), or greater than about 1.85 g/sec^(0.5), or greater than about 1.88 g/sec^(0.5), or greater than about 1.90 g/sec^(0.5), or greater than about 1.95 g/sec^(0.5), or greater than about 2.00 g/sec^(0.5), or between about 1.60 g/sec^(0.5) and about 2.50 g/sec^(0.5), or between about 1.65 g/sec^(0.5) and about 2.50 g/sec^(0.5), or between about 1.70 g/sec^(0.5) and about 2.40 g/sec^(0.5), or between about 1.75 g/sec^(0.5) and about 2.30 g/sec^(0.5), or between about 1.80 g/sec^(0.5) and about 2.20 g/sec^(0.5), or between about 1.82 g/sec^(0.5) and about 2.10 g/sec^(0.5), or between about 1.85 g/sec^(0.5) and about 2.00 g/sec^(0.5) as measured according to the SST Absorbency Rate Test Method described herein.

A Plate Stiffness value of greater than about 12 N*mm, or greater than about 12.5 N*mm, or greater than about 13.0 N*mm, or greater than about 13.5 N*mm, or greater than about 14 N*mm, or greater than about 14.5 N*mm, or greater than about 15 N*mm, or greater than about 15.5 N*mm, or greater than about 16 N*mm, or greater than about 16.5 N*mm, or greater than about 17 N*mm, or between about 12 N*mm and about 20 N*mm, or between about 12.5 N*mm and about 20 N*mm, or between about 13 N*mm and about 20 N*mm, or between about 13.5 N*mm and about 20 N*mm, or between about 14 N*mm between about 20 N*mm, or between about 14.5 N*mm and about 20 N*mm, or between about 15 N*mm and about 20 N*mm, or between about 15.5 N*mm and about 20 N*mm, or between about 16 N*mm and about 20 N*mm, or between about 16.5 N*mm and about 20 N*mm, or between about 17 N*mm and about 20 N*mm. To convert N*mm to g*mm multiply N value by 101.97 to obtain the g*mm value as measured according to the Plate Stiffness Test Method described herein.

A Resilient Bulk value of greater than about 85 cm³/g, or greater than about 90 cm³/g, or greater than about 95 cm³/g, or greater than about 100 cm³/g, or greater than about 102 cm³/g, or greater than about 105 cm³/g, or between about 85 cm³/g and about 110 cm³/g, or between about 90 cm³/g and about 110 cm³/g, or between about 95 cm³/g and about 110 cm³/g, or between about 100 cm³/g and about 110 cm³/g as measured according to the Stack Compressibility and Resilient Bulk Test Method described herein.

A Total Wet Tensile value of greater than about 400 g/in, or greater than about 450 g/in, or greater than about 500 g/in, or greater than about 550 g/in, or greater than about 600 g/in, or greater than about 650 g/in, or greater than about 700 g/in, or greater than about 750 g/in, or greater than about 800 g/in, or greater than about 850 g/in, or greater than about 900 g/in, or between about 400 Win and about 900 g/in, or between about 450 g/in and about 900 g/in, or between about 500 g/in and about 900 g/in, or between about 550 g/in and about 900 g/in, or between about 600 g/in and about 900 g/in, or between about 650 g/in and about 900 g/in, or between about 700 g/in and about 900 g/in as measured according to the Wet Tensile Test Method as described herein.

A Wet Burst value of greater than about 300 g, or greater than about 350 g, or greater than about 400 g, or greater than about 450 g, or greater than about 500 g, or greater than about 550 g, or greater than about 600 g, or between about 300 g and about 650 g, or between about 350 g and about 600 g, or between about 350 g and about 550 g, or between about 400 g and about 550 g, or between about 400 g and about 525 g as measured according to the Wet Burst Test Method described herein.

A Flexural Rigidity value of greater than about 700 mg-cm, or greater than about 800 mg-cm, or greater than about 900 mg-cm, or greater than about 1000 mg-cm, or greater than about 1100 mg-cm, or greater than about 1200 mg-cm, or greater than about 1300 mg-cm, or greater than about 1400 mg-cm, or greater than about 1500 mg-cm, or greater than about 1600 mg-cm, or greater than about 1700 mg-cm, or between about 700 mg-cm and about 1700 mg-cm, or between about 800 mg-cm and about 1500 mg-cm, or between about 900 mg-cm and about 1400 mg-cm, or between about 1000 mg-cm and about 1350 mg-cm, or between about 1050 mg-cm and about 1350 mg-cm, or between about 1100 mg-cm and about 1350 mg-cm, or between about 1100 mg-cm and about 1300 mg-cm as measured according to the Flexural Rigidity Test Method described herein.

A Dry Caliper value of greater than about 26.0 mils, or greater than about 40 mils, or between about 26.0 mils and about 80.0 mils, or between 40.0 mils and 60.0 mils, specifically reciting all 0.10 mil increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Caliper Test Method described herein.

A Wet Caliper value of greater than about 17.0 mils, or greater than about 26 mils, or between about 26.0 mils and about 70.0 mils, or between about 26.0 mils and about 40.0 mils, specifically reciting all 0.10 mil increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Caliper Test Method described herein.

A Total Dry Tensile (Total Tensile) value of greater than about 1300 g/in, or greater than about 1700 g/in, or between about 1300 g/in and about 8000 g/in, or between about 1800 g/in and about 7000 g/in or between about 2000 g/in and about 6000 g/in or between about 2000 g/in and 5000 g/in, specifically reciting all 10 g/in increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Dry Tensile Strength Test Method described herein.

A Geometric Mean Dry Modulus value of greater than about 1000 g/cm, or greater than about 1700 g/cm, or between about 1800 g/cm and about 4000 g/cm, or between about 1800 g/cm and about 3500 g/cm, specifically reciting all 10 g/cm increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Dry Modulus Test Method described herein.

A Wet Tensile Geometric Mean Modulus value of greater than about 250 g/cm, or greater than about 375 g/cm, or between about 250 g/cm and about 700 g/cm, or between about 250 g/cm and about 525 g/cm, or between about 375 g/cm and 525 g/cm, specifically reciting all 10 g/cm increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Wet Tensile Test Method described herein.

A CRT rate value of greater than about 0.30 g/sec, or greater than about 0.61 g/sec, or between about 0.30 g/sec and about 1.00 g/sec, or between about 0.61 g/sec and about 0.85 g/sec, specifically reciting all 0.05 g/sec increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the SST Absorbency Rate Test Method described herein.

A CRT capacity value of greater than about 10.0 g/g, or greater than about 12.5 g/g, or between about 12.5 g/g and about 23.0 g/g, or between about 16.5 g/g and about 21.5 g/g, specifically reciting all 0.1 g/g increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the SST Absorbency Rate Test Method described herein.

An Emtec TS750 value of greater than about 40 dB V² rms, or greater than about 50 dB V² rms, or between about 50 dB V² rms and about 100 dB V² rms, specifically reciting all 10 dB V² rms increments within the above-recited ranges and all ranges formed therein or thereby as measured according to the Emtec Test Method described herein.

A Slip Stick Coefficient of Friction (“Slip Stick COP”) value of greater than about 700, or between about 700 and about 1150, or between about 725 and about 1130 (COF*10000), specifically reciting all increments of 10 within the above-recited ranges and all ranges formed therein or thereby as measured according to the Slip Stick Coefficient of Friction Test Method described herein.

A Kinetic CoF value of greater than about 0.85, or between about 0.85 and about 1.30, or between about 0.85 and about 1.20, specifically reciting all 0.05 increments within the above-recited ranges and all ranges formed therein or thereby.

In one example, the fibrous structures and/or sanitary tissue products of the present invention may comprise a single-ply and exhibit a total dry tensile of at least 3000 g/in and/or at least 4000 g/in and/or at least 4500 g/in and/or at least 5000 g/in and/or at least 5500 g/in and/or at least 6000 g/in and comprise a surface pattern formed from the molding member shown in FIG. 1A or 1B.

In one example, the surface pattern of the fibrous structure according to the present invention comprises a continuous pillow network produced by a molding member 10, as shown in FIGS. 1A, and alternatively 1B, comprising a continuous pillow network deflection conduit 12 (represented by black lines throughout the pattern in FIGS. 1A and 1B), which imparts a continuous pillow network in a fibrous structure 16 in FIG. 1C made on such molding members 10, wherein the continuous pillow network deflection conduit 12 contains within it dispersed discrete zones/regions of a continuous knuckle network resin 18 (represented by white lines within the pattern in FIGS. 1A and 1B), which imparts one or more discrete, continuous knuckle networks 20 in FIG. 1C within the continuous pillow network in a fibrous structure 16 in FIG. 1C made on such molding members 10, wherein the discrete continuous network resin 18 in turn contains within it dispersed discrete pillow deflection conduits 22 (represented by black polygons within the pattern in FIGS. 1A and 1B), which imparts one or more discrete pillows 24 in FIG. 1C in a fibrous structure 16 in FIG. 1C made on such molding members 10, wherein the discrete pillows are dispersed throughout the discrete continuous knuckle network 20 as shown in FIG. 1C. Examples of fibrous structures made on such belts are shown images of FIG. 1C which shows two different magnifications and one fibrous structure containing viscose fibers (Danufil® fibers) and one fibrous structure that does not.

It has unexpectedly been found that the inclusion of synthetic fibers, for example viscose shifts the softness vs. pillow cell size equation. In known wet-laid fibrous structures, the larger the cell sizes (cell counts less than 120 and/or less than 100 and/or less than 95 and/or less than 80 and/or less than 75 and/or less than 50 and/or less than 25 cells/in²) the worse the surface softness. With the inclusion of viscose, larger cell sizes, for example larger pillows can be formed without negatively impacting softness and may increase softness.

Further, the large cells allow the longer (different modulus) viscose fibers to mold more effectively maximizing the potential in ply absorbency benefits.

In one example, as shown in FIG. 1A, the molding member 10 comprises large cells (discrete pillow deflection conduits 22) that exhibits a cell count of less than 120 and/or less than 100 and/or less than 90 and/or less than 75 and/or less than 50 and/or less than 30 and/or about 16 and/or about 12 cells/in². As used herein, the term “cell” is used to represent a discrete element, for example a discrete pillow deflection conduit in a molding member and/or a discrete resin element in a molding member; mainly a discrete pillow deflection conduit in a molding member, which imparts a discrete pillow to a surface pattern of the fibrous structure.

In one example, as shown in FIG. 1A, the molding member 10 comprises large cells (discrete pillow deflection conduits 22) that exhibits a cell count of less than 120 and/or less than 100 and/or less than 90 and/or less than 75 and/or less than 50 and/or less than 30 and/or about 25 cells/in². As used herein, the term “cell” is used to represent a discrete element, for example a discrete pillow deflection conduit in a molding member and/or a discrete resin element in a molding member; mainly a discrete pillow deflection conduit in a molding member, which imparts a discrete pillow to a surface pattern of the fibrous structure.

In one example, the fibrous structure of the present invention comprising a single-ply or multi-ply fibrous structure. In one example as shown in FIGS. 2A-4, the fibrous structure of the present invention comprises a multi-ply fibrous structure 26 comprising two plies. FIGS. 2A-2B shown the multi-ply fibrous structure 26 in dry states and wet states showing both discrete pillows 24 and discrete, continuous knuckles 20. The multi-ply fibrous structures 26 shown in FIGS. 2A and 2B comprise synthetic fibers, for example cellulose fibers, such as viscose fibers (Danufil® fibers), and pulp fibers, for example wood pulp fibers. FIGS. 3 and 4 shows images of both multi-ply fibrous structures 26 comprising no synthetic fibers, for example no viscose fibers, just pulp fibers, and multi-ply fibrous structures comprising synthetic fibers, for example cellulose fibers, such as viscose fibers (Danufil® fibers), and pulp fibers.

In one example, the fibrous structure of the present invention comprises a surface comprising a plurality of first pillows wherein at least a portion of the plurality of first pillows are at least partially bounded by at least a portion of a second pillow different from the plurality of first pillows, wherein the portion of the second pillow exhibits a maximum width that is less than the maximum dimension of one or more of the plurality of first pillows.

In one example, a portion of the plurality of first pillows of the fibrous structure of the present invention are fully bound by a portion of the second pillow of the fibrous structure.

In one example, the second pillow forms a continuous network pillow.

In one example, at least one of the plurality of first pillows exhibits a cell size of at least 16 cell/in² and/or at least 14 cell/in² and/or at least 12 cell/in².

In one example, at least one of the plurality of first pillows protrudes from the surface of the fibrous structure by greater than 0.025 inches and/or greater than 0.028 inches and/or greater than 0.030 inches.

In one example, a plurality of first pillows of the fibrous structure are separated from a second pillow of the fibrous structure by one or more knuckles, for example wherein at least a portion of at least one of the one or more knuckles is a continuous knuckle. In one example, a portion of the plurality of first pillows are dispersed throughout the continuous knuckle.

In one example, the fibrous structure of the present invention, comprises pulp fibers, for example wood pulp fibers. In one example, the fibrous structure of the present invention comprises non-wood pulp fibers. In still another example, the fibrous structure of the present invention comprises wood pulp fibers and non-wood pulp fibers.

In one example, the fibrous structure of the present invention comprises water-insensitive fibers. In one example, the plurality of first pillows of the fibrous structure of the present invention comprise water-insensitive fibers.

In one example, the fibrous structure of the present invention comprises synthetic fibers, for example synthetic fibers selected from the group consisting of: non-thermoplastic synthetic fibers, regenerated cellulose fibers and mixtures thereof. In one example, the regenerated cellulose fibers are selected from the group consisting of: rayon fibers, viscose fibers, and mixtures thereof. In one example, the regenerated cellulose fibers comprise viscose fibers.

In one example, the plurality of first pillows of the fibrous structure of the present invention comprises synthetic fibers.

In one example, the fibrous structure of the present invention exhibits a TS7 of less than 20 dB V² rms as measured according to the Emtec Test Method.

In one example, the plurality of first pillows of the fibrous structure of the present invention comprises greater than 80% of their original height (first pillows' original height) after wetting.

In one example, the fibrous structure of the present invention exhibits one or more of the following properties:

-   -   a. an SST value (absorbency rate) of less than about 1.60         g/sec^(0.5) and/or less than about 1.50 g/sec^(0.5) and/or less         than about 1.40 g/sec^(0.5) and/or less than about 1.30         g/sec^(0.5) and/or less than about 1.20 g/sec^(0.5);     -   b. a Plate Stiffness value of less than about 11 N*mm and/or         less than about 10 N*mm and/or less than about 9.0 N*mm and/or         less than about 8.0 N*mm (To convert N*mm to g*mm multiply N         value by 101.97 to obtain the g*mm value);     -   c. a Flexural Rigidity value of less than about 650 mg-cm and/or         less than about 625 mg-cm and/or less than about 600 mg-cm         and/or less than about 575 mg-cm and/or less than about 550         mg-cm and/or less than about 525 mg-cm and/or less than about         500 mg-cm and/or less than about 475 mg-cm;     -   d. a Flexural Rigidity to Total Dry Tensile Ratio of less than         about 0.3 and/or less than about 0.28 and/or less than about         0.25 and/or less than about 0.21 and/or less than about 0.20         and/or less than about 0.19;     -   e. a WTTF of greater than about 13 and/or greater than about 15         and/or greater than about 17 and/or greater than about 19 g/in;         and     -   f. a Residual Water value of less than about 1.10 and/or less         than about 1.00 and/or less than about 0.80 and/or less than         about 0.60 and/or less than about 0.50 and/or less than about         0.40%.

The fibrous structures, for example the multi-ply fibrous structures of the present invention exhibit improved properties compared to known fibrous structures. In one example, these improved properties are a result of the surface pattern imparted to the fibrous structures by the molding members, for example a molding member 10 as shown in FIG. 1A or 1B and/or the inclusion of synthetic fibers, such as viscose fibers, in the fibrous structures that create novel pillows in the fibrous structures.

Various properties of examples of fibrous structures of the present invention, for example multi-ply fibrous structures, Inventive Examples A-D formed on molding members shown in FIG. 1A or 1B, and various examples of Prior Art Paper Towels formed on molding members FIGS. 5-7, and other prior art paper towels are shown in Table 1 below. Prior Art FIG. 5 shows a molding member 10 comprising a continuous pillow network deflection conduit, continuous pillow network imparting deflection conduits (represented by the black lines) and discrete resin elements, knuckle imparting elements (represented by the white polygons). Prior Art FIG. 6 shows a molding member 10 comprising a continuous pillow network deflection conduit, continuous pillow network imparting deflection conduits (represented by the black lines) and discrete resin elements, knuckle imparting elements (represented by the various white shapes). Prior Art FIG. 7 shows a molding member 10 comprising a continuous pillow network deflection conduit, continuous pillow network imparting deflection conduits (represented by the black lines) and discrete resin elements, knuckle imparting elements (represented by the white H-shapes).

TABLE 1 BW CRT CRT CRT Total Dry Flexural (lbs/3000 Rate Capacity Capacity Tensile Rigidity Sample ft²) Plies (g/sec) (g/in²) Ratio (g/g) (g/in) (mg-cm) Invention A (FIG. 1A) - 42.05 2 0.54 0.74 17.46 2257.33 621.94 Does Not Contain Viscose Fibers Invention B (FIG. 1A) - 42.03 2 0.42 0.63 14.67 2262.78 503.07 Contains Viscose Fibers Invention C (FIG. 1B) - 39.61 2 0.44 0.73 17.38 2515.7 473.29 Contains Viscose Fibers Invention D (FIG. 1B) - 37.41 2 0.46 0.76 19.22 2588 470.99 Contains Viscose Fibers Prior Art Paper Towel 38.16 2 0.56 0.65 16.25 2046.33 656.75 Made By Molding Member of FIG. 6 - Contains Viscose Fibers Prior Art Paper Towel 38.27 2 0.69 0.78 19.4 2208 1035.00 Made By Molding Member of FIG. 6 - Does Not Contain Viscose Fibers Prior Art Paper Towel 35.5 2 0.71 0.70 18.56 2266.7 959.00 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 35.5 2 0.66 0.71 18.9 2329 1117.38 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 34.71 2 0.62 0.71 19.9 2511 1378.34 Made By Molding Member of FIG. 5 - Does Not Contain Viscose Fibers Prior Art Paper Towel — 2 — — — — 1357 Prior Art Paper Towel — 2 — — — — 1257.4 Prior Art Paper Towel — 2 0.74 — — — 1283.6 Prior Art Paper Towel — 2 0.79 — — — 1241.3 Prior Art Paper Towel — 2 0.76 — — — 1403.6 Prior Art Paper Towel — 2 0.68 — — — 1531.62 Prior Art Paper Towel — 2 0.84 — — — 1363.5 Prior Art Paper Towel — 2 0.81 — — — 1413 Flexural Rigidity/Total Plybond Residual Horizontal Horizontal Dry Tensile WTTF Tensile Water g/sht, g/g, Sample Ratio (g/in) (g/in) (%) Average Average Invention A (FIG. 1A) - 0.276 15.67 7.97 0.39 60.17 20.83 Does Not Contain Viscose Fibers Invention B (FIG. 1A) - 0.222 14.33 6.33 0.53 54.81 19.56 Contains Viscose Fibers Invention C (FIG. 1B) - 0.188 15 15.37 0.39 59.50 22.57 Contains Viscose Fibers Invention D (FIG. 1B) - 0.182 20 13.10 0.47 58.00 23.07 Contains Viscose Fibers Prior Art Paper Towel 0.321 11 5.87 1.34 49.10 19.27 Made By Molding Member of FIG. 6 - Contains Viscose Fibers Prior Art Paper Towel 0.469 12.3 5.20 1.90 59.00 22.90 Made By Molding Member of FIG. 6 - Does Not Contain Viscose Fibers Prior Art Paper Towel 0.423 11.7 7.80 2.33 53.00 22.43 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 0.480 11.4 19.8 2.80 55.91 23.81 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 0.549 11.4 17.1 3.20 56.83 24.53 Made By Molding Member of FIG. 5 - Does Not Contain Viscose Fibers Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Prior Art Paper Towel — — — — — — Vertical Vertical Wet Wet/Dry g/sht, g/g, Burst Dry Wet Caliper Sample Average Average (g) Caliper Caliper Ratio Invention A (FIG. 1A) - 24.57 8.5 n/a 46.27 27.63 0.6  Does Not Contain Viscose Fibers Invention B (FIG. 1A) - 26.5 9.46 443.33 41.05 26.3  0.65 Contains Viscose Fibers Invention C (FIG. 1B) - 26.93 10.20 461.33 37.87 25.17 0.66 Contains Viscose Fibers Invention D (FIG. 1B) - 26.33 10.47 511.33 40.17 24.40 0.61 Contains Viscose Fibers Prior Art Paper Towel 22.63 8.87 — — — — Made By Molding Member of FIG. 6 - Contains Viscose Fibers Prior Art Paper Towel 24.40 9.50 — — — — Made By Molding Member of FIG. 6 - Does Not Contain Viscose Fibers Prior Art Paper Towel 21.93 9.27 481.33 43.57 31.07 0.71 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 22.33 9.51 466.90 47.58 33.70 0.71 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 21.84 9.41 509.10 46.63 37.23 0.80 Made By Molding Member of FIG. 5 - Does Not Contain Viscose Fibers Prior Art Paper Towel — — 469 — — — Prior Art Paper Towel — — 434.7 — — — Prior Art Paper Towel — — 456 — — — Prior Art Paper Towel — — 528.3 — — — Prior Art Paper Towel — — 527.6 — — — Prior Art Paper Towel — — 463.3 — — — Prior Art Paper Towel — — 472.3 — — — Prior Art Paper Towel 483.7 EMTEC EMTEC TS7 TS750 SST Plate (dB V² (dB V² Kinetic (1.60 Stiffness Sample rms) rms) CoF g/sec^(0.5)) (N*mm) Invention A (FIG. 1A) - — — 0.9  — 7.49 Does Not Contain Viscose Fibers Invention B (FIG. 1A) - 14.78 77.21 1.18 1.19 7.45 Contains Viscose Fibers Invention C (FIG. 1B) - 16.95 65.50 1.07 1.25 7.66 Contains Viscose Fibers Invention D (FIG. 1B) - 18.35 63.77 1.06 1.35 7.11 Contains Viscose Fibers Prior Art Paper Towel — — — — — Made By Molding Member of FIG. 6 - Contains Viscose Fibers Prior Art Paper Towel — — — — — Made By Molding Member of FIG. 6 - Does Not Contain Viscose Fibers Prior Art Paper Towel 18.66 54.90 1.00 1.72 11.90 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 17.81 52.80 0.89 1.90 17.55 Made By Molding Member of FIG. 7 - Contains Viscose Fibers Prior Art Paper Towel 17.97 51.73 0.87 1.90 14.85 Made By Molding Member of FIG. 5 - Does Not Contain Viscose Fibers Prior Art Paper Towel 15.6 — — 2.37 14.38 Prior Art Paper Towel 14.68 — — 2.38 13.85 Prior Art Paper Towel 19.24 — — 2.27 14.26 Prior Art Paper Towel 18.7 — — 2.05 16.17 Prior Art Paper Towel 18.8 — — 2.03 16.43 Prior Art Paper Towel 16.41 — — 2.33 13.98 Prior Art Paper Towel 16.20 — — 2.42 13.64 Prior Art Paper Towel 15.10 — — 1.98 14.26

Molding Members

The fibrous structures and/or sanitary tissue products of the present invention and/or fibrous structure plies employed in the sanitary tissue products of the present invention are formed on molding members, for example patterned molding members, that result in the fibrous structures and/or sanitary tissue products of the present invention. In one example, the molding member comprises a non-random repeating pattern. In another example, the molding member comprises a resinous pattern.

A “reinforcing element” may be a desirable (but not necessary) element in some examples of the molding member, serving primarily to provide or facilitate integrity, stability, and durability of the molding member comprising, for example, a resinous material. The reinforcing element can be fluid-permeable or partially fluid-permeable, may have a variety of embodiments and weave patterns, and may comprise a variety of materials, such as, for example, a plurality of interwoven yarns (including Jacquard-type and the like woven patterns), a felt, a plastic, other suitable synthetic material, or any combination thereof.

As described herein, a non-limiting example of a molding member suitable for use in the present invention may comprise a through-air-drying belt comprising resin on a surface of and/or locked onto (for example a portion of the resin penetrates through) a reinforcing element in a pattern.

Without wishing to be bound by theory, foreshortening (dry & wet crepe, fabric crepe, rush transfer, etc) is an integral part of fibrous structure and/or sanitary tissue paper making, helping to produce the desired balance of strength, stretch, softness, absorbency, etc. Fibrous structure support, transport and molding members used in the papermaking process, such as rolls, wires, felts, fabrics, belts, etc. have been variously engineered to interact with foreshortening to further control the fibrous structure and/or sanitary tissue product properties.

In an example of a method for making fibrous structures of the present invention, the method can comprise the steps of:

-   -   (a) providing a fibrous furnish comprising fibers; and     -   (b) depositing the fibrous furnish onto a molding member such         that at least one fiber is deflected out-of-plane of the other         fibers present on the molding member.

In another example of a method for making a fibrous structure of the present invention, the method comprises the steps of:

-   -   (a) providing a fibrous furnish comprising fibers;     -   (b) depositing the fibrous furnish onto a foraminous member to         form an embryonic fibrous web;     -   (c) associating the embryonic fibrous web with a papermaking         belt having a pattern of knuckles as disclosed herein such that         at a portion of the fibers are deflected out-of-plane of the         other fibers present in the embryonic fibrous web; and     -   (d) drying said embryonic fibrous web such that that the dried         fibrous structure is formed.

In another example of a method for making the fibrous structures of the present invention, the method can comprise the steps of:

-   -   (a) providing a fibrous furnish comprising fibers;     -   (b) depositing the fibrous furnish onto a foraminous member such         that an embryonic fibrous web is formed;     -   (c) associating the embryonic web with a papermaking belt having         a pattern of knuckles as disclosed herein such that at a portion         of the fibers can be formed in the substantially continuous         deflection conduits;     -   (d) deflecting a portion of the fibers in the embryonic fibrous         web into the substantially continuous deflection conduits and         removing water from the embryonic web so as to form an         intermediate fibrous web under such conditions that the         deflection of fibers is initiated no later than the time at         which the water removal through the discrete deflection cells or         the substantially continuous deflection conduits is initiated;         and     -   (e) optionally, drying the intermediate fibrous web; and     -   (f) optionally, foreshortening the intermediate fibrous web,         such as by creping.

A non-limiting example of a process and equipment for making fibrous structures according to the present invention comprises supplying an aqueous dispersion of fibers (a fibrous furnish) to a headbox which can be of any design known to those of skill in the art. The aqueous dispersion of fibers can include wood and non-wood fibers, northern softwood kraft fibers (“NSK”), eucalyptus fibers, SSK, NHK, acacia, bamboo, straw and bast fibers (wheat, flax, rice, barley, etc.), corn stalks, bagasse, reed, synthetic fibers (PP, PET, PE, bico version of such fibers), regenerated cellulose fibers (viscose, lyocell, etc.), and other fibers known in the papermaking art. From the headbox, the aqueous dispersion of fibers can be delivered to a foraminous member, which can be a Fourdrinier wire, to produce an embryonic fibrous web.

The foraminous member can be supported by a breast roll and a plurality of return rolls of which only two are illustrated. The foraminous member can be propelled in the direction indicated by directional arrow by a drive means, at a predetermined velocity, V₁. Optional auxiliary units and/or devices commonly associated with fibrous structure making machines and with the foraminous member comprise forming boards, hydrofoils, vacuum boxes, tension rolls, support rolls, wire cleaning showers, and other various components known to those of skill in the art.

After the aqueous dispersion of fibers is deposited onto the foraminous member, the embryonic fibrous web is formed, typically by the removal of a portion of the aqueous dispersing medium by techniques known to those skilled in the art. Vacuum boxes, forming boards, hydrofoils, and other various equipment known to those of skill in the art are useful in effectuating water removal. The embryonic fibrous web can travel with the foraminous member about return roll and can be brought into contact with a papermaking belt in a transfer zone, after which the embryonic fibrous web travels on the papermaking belt. While in contact with the papermaking belt, the embryonic fibrous web can be deflected, rearranged, and/or further dewatered. Depending on the process, mechanical and fluid pressure differential, alone or in combination, can be utilized to deflect a portion of fibers into the deflection conduits of the papermaking belt. For example, in a through-air drying process a vacuum apparatus can apply a fluid pressure differential to the embryonic web disposed on the papermaking belt, thereby deflecting fibers into the deflection conduits of the deflection member. The process of deflection may be continued with additional vacuum pressure, if necessary, to even further deflect and dewater the fibers of the web into the deflection conduits of the papermaking belt.

The papermaking belt can be in the form of an endless belt. In this simplified representation, the papermaking belt passes around and about papermaking belt return rolls and impression nip roll and can travel in the direction indicated by directional arrow, at a papermaking belt velocity V₂, which can be less than, equal to, or greater than, the foraminous member velocity V₁. In the present invention, the papermaking belt velocity V₂ is less than foraminous member velocity V₁ such that the partially-dried fibrous web is foreshortened in the transfer zone by a percentage determined by the relative velocity differential between the foraminous member and the papermaking belt. Associated with the papermaking belt can be various support rolls, other return rolls, cleaning means, drive means, and other various equipment known to those of skill in the art that may be commonly used in fibrous structure making machines.

The papermaking belts of the present invention can be made, or partially made, according to the process described in U.S. Pat. No. 4,637,859, issued Jan. 20, 1987, to Trokhan, and having the patterns of cells as disclosed herein.

The fibrous web can then be creped with a creping blade to remove the web from the surface of the Yankee dryer resulting in the production of a creped fibrous structure in accordance with the present invention. As used herein, creping refers to the reduction in length of a dry (having a consistency of at least about 90% and/or at least about 95%) fibrous web which occurs when energy is applied to the dry fibrous web in such a way that the length of the fibrous web is reduced and the fibers in the fibrous web are rearranged with an accompanying disruption of fiber-fiber bonds. Creping can be accomplished in any of several ways as is well known in the art, as the doctor blades can be set at various angles. The creped fibrous structure is wound on a reel, commonly referred to as a parent roll, and can be subjected to post processing steps such as calendaring, tuft generating operations, embossing, and/or converting. The reel winds the creped fibrous structure at a reel surface velocity, V₄.

The papermaking belts of the present invention can be utilized to form discrete elements and a continuous/substantially continuous network (i.e., knuckles and pillows) into a fibrous structure during a through-air-drying operation. The discrete elements can be knuckles and can be relatively high density relative to the continuous/substantially continuous network, which can be a continuous/substantially pillow having a relatively lower density. In other examples, the discrete elements can be pillows and can be relatively low density relative to the continuous/substantially continuous network, which can be a continuous/substantially continuous knuckle having a relatively higher density. In the example detailed above, the fibrous structure is a homogenous fibrous structure, but such papermaking process may also be adapted to manufacture layered fibrous structures, as is known in the art.

As discussed above, the fibrous structure can be embossed during a converting operating to produce the embossed fibrous structures of the present invention.

In one example, fibrous structures of the present invention may comprise discrete pillows that are imparted by a molding member comprising a continuous pillow network deflection conduit and a plurality of discrete pillow conduits (cell count of less than 90 and/or less than 75 and/or less than 50 and/or less than 25 and/or less than 20 and/or about 16 cells/in²). The discrete pillow conduits may be dispersed within a discrete, continuous network resin, which itself is dispersed within the continuous pillow network deflection conduit.

In one example, fibrous structures of the present invention may comprise discrete pillows that are imparted by a molding member comprising a continuous network resin (that imparts a knuckle) wherein the plurality of discrete pillow conduits are present at a cell count of less than 20 and/or about 16 cells/in²). The discrete pillow conduits are dispersed within the continuous network resin.

In one example, fibrous structures of the present invention may comprise discrete pillows of from 0.01 inch to 1.0 inch cell size and overburden (height of pillows or depth of discrete pillow conduits) of greater than 0.025 inches and/or greater than 0.028 inches and/or greater than 0.030 inches wherein the fibrous structure comprises synthetic fibers, for example viscose fibers, and pulp fibers.

Non-Limiting Examples of Making Fibrous Structures and/or Sanitary Tissue Products

In one example, the method for making the fibrous structures and/or sanitary tissue products of the present invention may be a fibrous structure and/or sanitary tissue product making process that uses a cylindrical dryer such as a Yankee (a Yankee-process) or it may be a Yankeeless process as is used to make substantially uniform density and/or uncreped fibrous structures and/or sanitary tissue products. Alternatively, the fibrous structures and/or sanitary tissue products may be made by an air-laid process and/or meltblown and/or spunbond processes and any combinations thereof so long as the fibrous structures and/or sanitary tissue products of the present invention are made thereby.

As shown in FIG. 8, one example of a process and equipment, represented as 100 for making a sanitary tissue product according to the present invention comprises supplying an aqueous dispersion of fibers (a fibrous furnish or fiber slurry) to a headbox 102 which can be of any convenient design. From headbox 102 the aqueous dispersion of fibers is delivered to a first foraminous member 104 which is typically a Fourdrinier wire, to produce an embryonic fibrous structure 106.

The first foraminous member 104 may be supported by a breast roll 108 and a plurality of return rolls 110 of which only two are shown. The first foraminous member 104 can be propelled in the direction indicated by directional arrow 112 by a drive means, not shown. Optional auxiliary units and/or devices commonly associated fibrous structure making machines and with the first foraminous member 104, but not shown, include forming boards, hydrofoils, vacuum boxes, tension rolls, support rolls, wire cleaning showers, and the like.

After the aqueous dispersion of fibers is deposited onto the first foraminous member 104, embryonic fibrous structure 106 is formed, typically by the removal of a portion of the aqueous dispersing medium by techniques well known to those skilled in the art. Vacuum boxes, forming boards, hydrofoils, and the like are useful in effecting water removal. The embryonic fibrous structure 106 may travel with the first foraminous member 104 about return roll 110 and is brought into contact with a patterned molding member 114 (also referred to herein as molding member 10), such as a 3D patterned through-air-drying belt. While in contact with the patterned molding member 114, the embryonic fibrous structure 106 will be deflected, rearranged, and/or further dewatered.

The patterned molding member 114 may be in the form of an endless belt. In this simplified representation, the patterned molding member 114 passes around and about patterned molding member return rolls 116 and impression nip roll 118 and may travel in the direction indicated by directional arrow 120. Associated with patterned molding member 114, but not shown, may be various support rolls, other return rolls, cleaning means, drive means well known to those skilled in the art that may be commonly used in fibrous structure making machines.

After the embryonic fibrous structure 106 has been associated with the patterned molding member 114, fibers within the embryonic fibrous structure 106 are deflected into pillows and/or pillow network (“deflection conduits”) present in the patterned molding member 114. In one example of this process step, there is essentially no water removal from the embryonic fibrous structure 106 through the deflection conduits after the embryonic fibrous structure 106 has been associated with the patterned molding member 114 but prior to the deflecting of the fibers into the deflection conduits. Further water removal from the embryonic fibrous structure 106 can occur during and/or after the time the fibers are being deflected into the deflection conduits. Water removal from the embryonic fibrous structure 106 may continue until the consistency of the embryonic fibrous structure 106 associated with patterned molding member 114 is increased to from about 25% to about 35%. Once this consistency of the embryonic fibrous structure 106 is achieved, then the embryonic fibrous structure 106 can be referred to as an intermediate fibrous structure 122. During the process of forming the embryonic fibrous structure 106, sufficient water may be removed, such as by a noncompressive process, from the embryonic fibrous structure 106 before it becomes associated with the patterned molding member 114 so that the consistency of the embryonic fibrous structure 116 may be from about 10% to about 30%.

While applicants decline to be bound by any particular theory of operation, it appears that the deflection of the fibers in the embryonic fibrous structure and water removal from the embryonic fibrous structure begin essentially simultaneously. Embodiments can, however, be envisioned wherein deflection and water removal are sequential operations. Under the influence of the applied differential fluid pressure, for example, the fibers may be deflected into the deflection conduit with an attendant rearrangement of the fibers. Water removal may occur with a continued rearrangement of fibers. Deflection of the fibers, and of the embryonic fibrous structure, may cause an apparent increase in surface area of the embryonic fibrous structure. Further, the rearrangement of fibers may appear to cause a rearrangement in the spaces or capillaries existing between and/or among fibers.

It is believed that the rearrangement of the fibers can take one of two modes dependent on a number of factors such as, for example, fiber length. The free ends of longer fibers can be merely bent in the space defined by the deflection conduit while the opposite ends are restrained in the region of the ridges. Shorter fibers, on the other hand, can actually be transported from the region of the ridges into the deflection conduit (The fibers in the deflection conduits will also be rearranged relative to one another). Naturally, it is possible for both modes of rearrangement to occur simultaneously.

As noted, water removal occurs both during and after deflection; this water removal may result in a decrease in fiber mobility in the embryonic fibrous structure. This decrease in fiber mobility may tend to fix and/or freeze the fibers in place after they have been deflected and rearranged. Of course, the drying of the fibrous structure in a later step in the process of this invention serves to more firmly fix and/or freeze the fibers in position.

Any convenient means conventionally known in the papermaking art can be used to dry the intermediate fibrous structure 122. Examples of such suitable drying process include subjecting the intermediate fibrous structure 122 to conventional and/or flow-through dryers and/or Yankee dryers.

In one example of a drying process, the intermediate fibrous structure 122 in association with the patterned molding member 114 passes around the patterned molding member return roll 116 and travels in the direction indicated by directional arrow 120. The intermediate fibrous structure 122 may first pass through an optional predryer 124. This predryer 124 can be a conventional flow-through dryer (hot air dryer) well known to those skilled in the art. Optionally, the predryer 124 can be a so-called capillary dewatering apparatus. In such an apparatus, the intermediate fibrous structure 122 passes over a sector of a cylinder having preferential-capillary-size pores through its cylindrical-shaped porous cover. Optionally, the predryer 124 can be a combination capillary dewatering apparatus and flow-through dryer. The quantity of water removed in the predryer 124 may be controlled so that a predried fibrous structure 126 exiting the predryer 124 has a consistency of from about 30% to about 98%. The predried fibrous structure 126, which may still be associated with patterned molding member 114, may pass around another patterned molding member return roll 116 and as it travels to an impression nip roll 118. As the predried fibrous structure 126 passes through the nip formed between impression nip roll 118 and a surface of a Yankee dryer 128, the pattern formed by the top surface 130 of patterned molding member 114 is impressed into the predried fibrous structure 126 to form a 3D patterned fibrous structure 132. The imprinted fibrous structure 132 can then be adhered to the surface of the Yankee dryer 128 where it can be dried to a consistency of at least about 95%.

The 3D patterned fibrous structure 132 can then be foreshortened by creping the 3D patterned fibrous structure 132 with a creping blade 133 to remove the 3D patterned fibrous structure 132 from the surface of the Yankee dryer 128 resulting in the production of a 3D patterned creped fibrous structure 134 in accordance with the present invention, wherein the 3D patterned creped fibrous structure has a fabric-side-out (FSO) surface that has pillows imparted to it by the patterned molding member 114 protruding outward and a wire-side-out (WSO) surface that did not contact the patterned molding member 114 during the making process, but rather contacted the first foraminous member 104, in this case the Fourdrinier wire. As used herein, foreshortening refers to the reduction in length of a dry (having a consistency of at least about 90% and/or at least about 95%) fibrous structure which occurs when energy is applied to the dry fibrous structure in such a way that the length of the fibrous structure is reduced and the fibers in the fibrous structure are rearranged with an accompanying disruption of fiber-fiber bonds. Foreshortening can be accomplished in any of several well-known ways. One common method of foreshortening is creping. The 3D patterned creped fibrous structure 134 may be subjected to post processing steps such as calendaring, tuft generating operations, and/or embossing and/or converting.

Another example of making fibrous structures, for example paper towels, in accordance with the present invention using the papermaking machine described in FIG. 8 is described below.

A 3% by weight aqueous slurry of northern softwood kraft (NSK) pulp is made up in a conventional re-pulper. The NSK slurry is refined gently and a 2% solution of a permanent wet strength resin (i.e. Kymene 5221 marketed by Solenis incorporated of Wilmington, Del.) is added to the NSK stock pipe at a rate of 1% by weight of the dry fibers. Kymene 522 μs added as a wet strength additive. The adsorption of Kymene 5221 to NSK is enhanced by an in-line mixer. A 1% solution of Carboxy Methyl Cellulose (CMC) (i.e. FinnFix 700 marketed by C.P. Kelco U.S. Inc. of Atlanta, Ga.) is added after the in-line mixer at a rate of 0.2% by weight of the dry fibers to enhance the dry strength of the fibrous substrate. A 3% by weight aqueous slurry of hardwood Eucalyptus fibers is made up in a conventional re-pulper. A 1% solution of defoamer (i.e. BuBreak 4330 marketed by Buckman Labs, Memphis TS) is added to the Eucalyptus stock pipe at a rate of 0.25% by weight of the dry fibers and its adsorption is enhanced by an in-line mixer.

The NSK furnish and the Eucalyptus fibers are combined in the head box and deposited onto a Fourdrinier wire, running at a first velocity V₁, homogenously to form an embryonic web. The web is then transferred at the transfer zone from the Fourdrinier forming wire at a fiber consistency of about 15% to the papermaking belt, the papermaking belt moving at a second velocity, V₂. The papermaking belt has a pattern of raised portions (i.e., knuckles) extending from a reinforcing member, the raised portions defining either a plurality of discrete or a continuous/substantially continuous deflection conduit portion. The transfer occurs in the transfer zone without precipitating substantial densification of the web. The web is then forwarded, at the second velocity, V₂, on the papermaking belt along a looped path in contacting relation with a transfer head disposed at the transfer zone, the second velocity being from about 1% to about 40% slower than the first velocity, V₁. Since the Fourdrinier wire speed is faster than the papermaking belt, wet shortening, i.e., foreshortening, of the web occurs at the transfer point. In an example, the second velocity V₂ can be from about 0% to about 5% faster than the first velocity V₁.

Further de-watering is accomplished by vacuum assisted drainage until the web has a fiber consistency of about 15% to about 30%. The patterned web is pre-dried by air blow-through, i.e., through-air-drying (TAD), to a fiber consistency of about 65% by weight. The web is then adhered to the surface of a Yankee dryer with a sprayed creping adhesive comprising 0.25% aqueous solution of polyvinyl alcohol (PVA). The fiber consistency is increased to an estimated 95%-97% before dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 45 degrees and is positioned with respect to the Yankee dryer to provide an impact angle of about 101 degrees. This doctor blade position permits the adequate amount of force to be applied to the substrate to remove it off the Yankee while minimally disturbing the previously generated web structure. The dried web is reeled onto a take up roll (known as a parent roll), the surface of the take up roll moving at a fourth velocity, V₄, that is faster than the third velocity, V₃, of the Yankee dryer. By reeling at a fourth velocity, V₄, that is about 1% to 20% faster than the third velocity, V₃, some of the foreshortening provided by the creping step is “pulled out,” sometimes referred to as a “positive draw,” so that the paper can be more stable for any further converting operations. In other examples, a “negative draw” as is known in the art is also contemplated.

Two plies of the web can be formed into paper towel products by embossing and laminating them together using PVA adhesive. The paper towel has about 53 g/m² basis weight and contains 65% by weight Northern Softwood Kraft and 35% by weight Eucalyptus furnish. The sanitary tissue product is soft, flexible and absorbent.

NON-LIMITING EXAMPLES OF MAKING FIBROUS STRUCTURES Example 1—A Fibrous Structure of the Present Invention

Examples of dry fibrous structures; namely, paper towels, are produced utilizing a cellulosic pulp fiber furnish consisting of about 48% Northern Bleached Softwood Kraft (“NSK”) (Resolute), about 20% viscose fibers (Danufil®-Kelheim-fibres), about 20% Eucalyptus Bleached Kraft (“Euc”) (Fibria), and about 12% simulated broke. Any furnish preparation and refining methodology common to the papermaking industry can be utilized.

A 3% active solution Kymene 5221 is added to the NSK prior to an in-line static mixer to make an NSK fiber stream and 1% active solution of Wickit 1285, an ethoxylated fatty alcohol available from Ashland Inc., is added to the Euc to make a Euc fiber stream. The addition levels of the respective active solutions are 21 and 1 lbs active/ton of paper towel (fibrous structure), respectively. The NSK fiber stream, Euc fiber stream, viscose fiber stream, and simulated broke fiber stream are separate streams until combining in the headbox.

A 1% active carboxymethylcellulose (CMC-Finnfix) solution at a total level of 7 lbs active/ton of paper towel is added to the NSK fiber stream and/or Euc fiber stream.

The NSK fiber stream, Euc fiber stream, viscose fiber stream, and simulated broke fiber stream are then combined and then diluted with white water at the inlet of a fan pump to a consistency of about 0.15% based on total weight of NSK fibers, Euc fibers, viscose fibers and simulated broke fiber. The diluted fiber slurry is then directed to a non-layered configuration headbox such that an embryonic wet web is formed onto a Fourdrinier wire (foraminous wire). Optionally, a fines retention/drainage aid may be added to the outlet of the fan pump.

Dewatering occurs through the Fourdrinier wire and is assisted by deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 87 machine-direction and 76 cross-direction monofilaments per inch, respectively. The speed of the Fourdrinier wire is about 750 fpm (feet per minute).

The embryonic wet web is transferred from the Fourdrinier wire at a fiber consistency of about 24% at the point of transfer, to a patterned belt, such as a patterned belt through-air-drying resin carrying fabric, for example a molding member, such as the molding member as shown in FIG. 1A. In the present case, the speed of the patterned belt is traveling slower, for example about 20% slower than the speed of the Fourdrinier wire (for example a wet molding process).

Further de-watering is accomplished by vacuum assisted drainage until the web (fibrous structure) has a fiber consistency of about 30%.

While remaining in contact with the patterned belt, the web is pre-dried by air blow-through pre-dryers to a fiber consistency of about 65% by weight.

After the pre-dryers, the semi-dry web is transferred to a Yankee dryer and adhered to the surface of the Yankee dryer with a sprayed creping adhesive. The creping adhesive is an aqueous dispersion with the actives consisting of about 75% polyvinyl alcohol, and about 25% CREPETROL® R6390. Optionally a crepe aid consisting of CREPETROL® A3025 may be applied. CREPETROL® R6390 and CREPETROL® A3025 are commercially available from Ashland Inc. (formerly Hercules Inc.). The creping adhesive diluted to about 0.15% adhesive solids and delivered to the Yankee surface at a rate of about 2 # adhesive solids based on the dry weight of the web. The fiber consistency is increased to about 97% before the web is dry creped from the Yankee with a doctor blade.

In the present case, the doctor blade has a bevel angle of about 45° and is positioned with respect to the Yankee dryer to provide an impact angle of about 101° and the reel is run at a speed that is about 15% faster than the speed of the Yankee. In another case, the doctor blade may have a bevel angle of about 25° and be positioned with respect to the Yankee dryer to provide an impact angle of about 81° and the reel is run at a speed that is about 10% slower than the speed of the Yankee. The Yankee dryer is operated at a temperature of about 177° C. and a speed of about 800 fpm. The fibrous structure is wound in a roll using a surface driven reel drum having a surface speed of about 656 feet per minute. The fibrous structure is made at a basis weight of from about 70 gsm to about 90 gsm, for example about 81 gsm. The creped fibrous structure after removal from the Yankee dryer exhibits both a fabric-side-out (FSO) surface (the surface not contacting the Yankee dryer in this case), and a wire-side-out (WSO) surface (the surface contacting the Yankee dryer in this case).

The fibrous structure exhibits the following properties: 1) FSO Moist Contact Area of 14.5% and FSO Moist Depth of less than −375 μm and/or less than −400 μm; namely −418 μm (Inventive Point 1 on Moist Contact Area (%) to Moist Depth (μm) graph in FIG. 9) and WSO Moist Contact Area of 21.8% and WSO Moist Depth of less than −375 μm and/or less than −400 μm; namely −401 μm (Inventive Point 2 on Moist Contact Area (%) to Moist Depth (μm) graph in FIG. 9) as measured according to the Moist Towel Surface Structure Test Method described herein.

Example 2—A Fibrous Structure of the Present Invention

Examples of dry fibrous structures; namely, paper towels, are produced utilizing a cellulosic pulp fiber furnish consisting of about 48% Northern Bleached Softwood Kraft (“NSK”) (Resolute), about 40% Eucalyptus Bleached Kraft (“Euc”) (Fibria), and about 12% simulated broke. Any furnish preparation and refining methodology common to the papermaking industry can be utilized.

A 3% active solution Kymene 5221 is added to the NSK prior to an in-line static mixer to make an NSK fiber stream and 1% active solution of Wickit 1285, an ethoxylated fatty alcohol available from Ashland Inc., is added to the Euc to make a Euc fiber stream. The addition levels of the respective active solutions are 21 and 1 lbs active/ton of paper towel (fibrous structure), respectively. The NSK fiber stream, Euc fiber stream, and simulated broke fiber stream are separate streams until combining in the headbox.

A 1% active carboxymethylcellulose (CMC-Finnfix) solution at a total level of 7 lbs active/ton of paper towel is added to the NSK fiber stream and/or Euc fiber stream.

The NSK fiber stream, Euc fiber stream, and simulated broke fiber stream are then combined and then diluted with white water at the inlet of a fan pump to a consistency of about 0.15% based on total weight of NSK fibers, Euc fibers, and simulated broke fiber. The diluted fiber slurry is then directed to a non-layered configuration headbox such that an embryonic wet web is formed onto a Fourdrinier wire (foraminous wire). Optionally, a fines retention/drainage aid may be added to the outlet of the fan pump.

Dewatering occurs through the Fourdrinier wire and is assisted by deflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satin weave configuration having 87 machine-direction and 76 cross-direction monofilaments per inch, respectively. The speed of the Fourdrinier wire is about 750 fpm (feet per minute).

The embryonic wet web is transferred from the Fourdrinier wire at a fiber consistency of about 24% at the point of transfer, to a patterned belt, such as a patterned belt through-air-drying resin carrying fabric, for example a molding member, such as the molding member as shown in FIG. 1A. In the present case, the speed of the patterned belt is traveling slower, for example about 20% slower than the speed of the Fourdrinier wire (for example a wet molding process).

Further de-watering is accomplished by vacuum assisted drainage until the web (fibrous structure) has a fiber consistency of about 30%.

While remaining in contact with the patterned belt, the web is pre-dried by air blow-through pre-dryers to a fiber consistency of about 65% by weight.

After the pre-dryers, the semi-dry web is transferred to a Yankee dryer and adhered to the surface of the Yankee dryer with a sprayed creping adhesive. The creping adhesive is an aqueous dispersion with the actives consisting of about 75% polyvinyl alcohol, and about 25% CREPETROL® R6390. Optionally a crepe aid consisting of CREPETROL® A3025 may be applied. CREPETROL® R6390 and CREPETROL® A3025 are commercially available from Ashland Inc. (formerly Hercules Inc.). The creping adhesive diluted to about 0.15% adhesive solids and delivered to the Yankee surface at a rate of about 2 # adhesive solids based on the dry weight of the web. The fiber consistency is increased to about 97% before the web is dry creped from the Yankee with a doctor blade.

In the present case, the doctor blade has a bevel angle of about 45° and is positioned with respect to the Yankee dryer to provide an impact angle of about 101° and the reel is run at a speed that is about 15% faster than the speed of the Yankee. In another case, the doctor blade may have a bevel angle of about 25° and be positioned with respect to the Yankee dryer to provide an impact angle of about 81° and the reel is run at a speed that is about 10% slower than the speed of the Yankee. The Yankee dryer is operated at a temperature of about 177° C. and a speed of about 800 fpm. The fibrous structure is wound in a roll using a surface driven reel drum having a surface speed of about 656 feet per minute. The fibrous structure is made at a basis weight of from about 70 gsm to about 90 gsm, for example about 81 gsm. The creped fibrous structure after removal from the Yankee dryer exhibits both a fabric-side-out (FSO) surface (the surface not contacting the Yankee dryer in this case), and a wire-side-out (WSO) surface (the surface contacting the Yankee dryer in this case).

Test Methods

Unless otherwise specified, all tests described herein including those described under the Definitions section and the following test methods are conducted on samples that have been conditioned in a conditioned room at a temperature of 23° C.±1.0° C. and a relative humidity of 50%±2% for a minimum of 2 hours prior to the test. The samples tested are “usable units.” “Usable units” as used herein means sheets, flats from roll stock, pre-converted flats, and/or single or multi-ply products. All tests are conducted in such conditioned room. Do not test samples that have defects such as wrinkles, tears, holes, and like. All instruments are calibrated according to manufacturer's specifications.

Emtec Test Method:

TS7 and TS750 values are measured using an EMTEC Tissue Softness Analyzer (“Emtec TSA”) (Emtec Electronic GmbH, Leipzig, Germany) interfaced with a computer running Emtec TSA software (version 3.19 or equivalent). According to Emtec, the TS7 value correlates with the real material softness, while the TS750 value correlates with the felt smoothness/roughness of the material. The Emtec TSA comprises a rotor with vertical blades which rotate on the test sample at a defined and calibrated rotational speed (set by manufacturer) and contact force of 100 mN. Contact between the vertical blades and the test piece creates vibrations, which create sound that is recorded by a microphone within the instrument. The recorded sound file is then analyzed by the Emtec TSA software. The sample preparation, instrument operation and testing procedures are performed according the instrument manufacture's specifications.

Sample Preparation

Test samples are prepared by cutting square or circular samples from a finished product. Test samples are cut to a length and width (or diameter if circular) of no less than about 90 mm, and no greater than about 120 mm, in any of these dimensions, to ensure the sample can be clamped into the TSA instrument properly. Test samples are selected to avoid perforations, creases or folds within the testing region. Prepare 8 substantially similar replicate samples for testing. Equilibrate all samples at TAPPI standard temperature and relative humidity conditions (23° C.±2 C.° and 50%±2%) for at least 1 hour prior to conducting the TSA testing, which is also conducted under TAPPI conditions.

Testing Procedure

Calibrate the instrument according to the manufacturer's instructions using the 1-point calibration method with Emtec reference standards (“ref.2 samples”). If these reference samples are no longer available, use the appropriate reference samples provided by the manufacturer. Calibrate the instrument according to the manufacturer's recommendation and instruction, so that the results will be comparable to those obtained when using the 1-point calibration method with Emtec reference standards (“ref.2 samples”).

Mount the test sample into the instrument, and perform the test according to the manufacturer's instructions. When complete, the software displays values for TS7 and TS750. Record each of these values to the nearest 0.01 dB V² rms. The test piece is then removed from the instrument and discarded. This testing is performed individually on the top surface (outer facing surface of a rolled product) of four of the replicate samples, and on the bottom surface (inner facing surface of a rolled product) of the other four replicate samples.

The four test result values for TS7 and TS750 from the top surface are averaged (using a simple numerical average); the same is done for the four test result values for TS7 and TS750 from the bottom surface. Report the individual average values of TS7 and TS750 for both the top and bottom surfaces on a particular test sample to the nearest 0.01 dB V² rms. Additionally, average together all eight test value results for TS7 and TS750, and report the overall average values for TS7 and TS750 on a particular test sample to the nearest 0.01 dB V² rms.

Basis Weight Test Method:

Basis weight of a fibrous structure and/or sanitary tissue product is measured on stacks of twelve usable units using a top loading analytical balance with a resolution of ±0.001 g. The balance is protected from air drafts and other disturbances using a draft shield. A precision cutting die, measuring 3.500 in ±0.0035 in by 3.500 in ±0.0035 in is used to prepare all samples.

With a precision cutting die, cut the samples into squares. Combine the cut squares to form a stack twelve samples thick. Measure the mass of the sample stack and record the result to the nearest 0.001 g.

The Basis Weight is calculated in lbs/3000 ft² or g/m² as follows:

Basis Weight=(Mass of stack)/[(Area of 1 square in stack)×(No. of squares in stack)]

For example,

Basis Weight(lbs/3000 ft²)=[[Mass of stack(g)/453.6(g/lbs)]/[12.25(in²)/144(in²/ft²)×12]]×3000

or,

Basis Weight(g/m²)=Mass of stack(g)/[79.032(cm²)/10,000(cm²/m²)×12]

Report result to the nearest 0.1 lbs/3000 ft² or 0.1 g/m². Sample dimensions can be changed or varied using a similar precision cutter as mentioned above, so as at least 100 square inches of sample area in stack.

Crystallinity Test Method:

The crystallinity of a surfactant composition (aqueous solution of surfactants or a surfactant paste composition), 100 μL of the surfactant composition (33.3 parts surfactant composition and 66.7 parts distilled water) to be tested is added to a glass microscope slide. The slide is left to rest at 25° C. for 7 days to dry and permit any crystallizatine arrangement to occur. A cover slide is then added to the glass microscope slide to sandwich the dried surfactant composition between the glass microscope slide and the cover slide. A standard optical microscope (Nikon 516096 or equivalent) with a 0-360° rotational angle polarizer (Nikon Phase Contrast T-2 15957 or equivalent) was then used to view the surfactant composition. This crystallinity test method identifies surfactant compositions based on type and amount of crystallinity, for example crystal aggregation versus no crystal aggregation, birefringence versus no birefringence.

Caliper Test Method:

Caliper of a fibrous structure and/or sanitary tissue product is measured using a ProGage Thickness Tester (Thwing-Albert Instrument Company, West Berlin, N.J.) with a pressure foot diameter of 2.00 inches (area of 3.14 in²) at a pressure of 95 g/in². Four (4) samples are prepared by cutting of a usable unit such that each cut sample is at least 2.5 inches per side, avoiding creases, folds, and obvious defects. An individual specimen is placed on the anvil with the specimen centered underneath the pressure foot. The foot is lowered at 0.03 in/sec to an applied pressure of 95 g/in². The reading is taken after 3 sec dwell time, and the foot is raised. The measure is repeated in like fashion for the remaining 3 specimens. The caliper is calculated as the average caliper of the four specimens and is reported in mils (0.001 in) to the nearest 0.1 mils.

Density Test Method:

The density of a fibrous structure and/or sanitary tissue product is calculated as the quotient of the Basis Weight of a fibrous structure or sanitary tissue product expressed in lbs/3000 ft² divided by the Caliper (at 95 g/in²) of the fibrous structure or sanitary tissue product expressed in mils. The final Density value is calculated in lbs/ft³ and/or g/cm³, by using the appropriate converting factors.

SST Absorbency Rate Test Method:

This test incorporates the Slope of the Square Root of Time (SST) Test Method. The SST method measures rate over a wide spectrum of time to capture a view of the product pick-up rate over the useful lifetime. In particular, the method measures the absorbency rate via the slope of the mass versus the square root of time from 2-15 seconds.

Overview

The absorption (wicking) of water by a fibrous sample is measured over time. A sample is placed horizontally in the instrument and is supported with minimal contact during testing (without allowing the sample to droop) by an open weave net structure that rests on a balance. The test is initiated when a tube connected to a water reservoir is raised and the meniscus makes contact with the center of the sample from beneath, at a small negative pressure. Absorption is controlled by the ability of the sample to pull the water from the instrument for approximately 20 seconds. Rate is determined as the slope of the regression line of the outputted weight vs sqrt(time) from 2 to 15 seconds.

Apparatus

Conditioned Room—Temperature is controlled from 73° F.±2° F. (23° C.±1° C.). Relative Humidity is controlled from 50%+2%

Sample Preparation—Product samples are cut using hydraulic/pneumatic precision cutter into 3.375 inch diameter circles.

Capacity Rate Tester (CRT)—The CRT is an absorbency tester capable of measuring capacity and rate. The CRT consists of a balance (0.001 g), on which rests on a woven grid (using nylon monofilament line having a 0.014″ diameter) placed over a small reservoir with a delivery tube in the center. This reservoir is filled by the action of solenoid valves, which help to connect the sample supply reservoir to an intermediate reservoir, the water level of which is monitored by an optical sensor. The CRT is run with a −2 mm water column, controlled by adjusting the height of water in the supply reservoir.

A diagram of the testing apparatus set up is shown in FIG. 10.

Software—LabView based custom software specific to CRT Version 4.2 or later.

Water—Distilled water with conductivity <10 μS/cm (target <5 μS/cm) @ 25° C.

Sample Preparation

For this method, a usable unit is described as one finished product unit regardless of the number of plies. Condition all samples with packaging materials removed for a minimum of 2 hours prior to testing. Discard at least the first ten usable units from the roll. Remove two usable units and cut one 3.375-inch circular sample from the center of each usable unit for a total of 2 replicates for each test result. Do not test samples with defects such as wrinkles, tears, holes, etc. Replace with another usable unit which is free of such defects

Sample Testing Pre-Test Set-Up

-   -   1. The water height in the reservoir tank is set −2.0 mm below         the top of the support rack (where the towel sample will be         placed).     -   2. The supply tube (8 mm I.D.) is centered with respect to the         support net.     -   3. Test samples are cut into circles of 3⅜″ diameter and         equilibrated at Tappi environment conditions for a minimum of 2         hours.

Test Description

-   -   1. After pressing the start button on the software application,         the supply tube moves to 0.33 mm below the water height in the         reserve tank. This creates a small meniscus of water above the         supply tube to ensure test initiation. A valve between the tank         and the supply tube closes, and the scale is zeroed.     -   2. The software prompts you to “load a sample”. A sample is         placed on the support net, centering it over the supply tube,         and with the side facing the outside of the roll placed         downward.     -   3. Close the balance windows and press the “OK” button—the         software records the dry weight of the circle.     -   4. The software prompts you to “place cover on sample”. The         plastic cover is placed on top of the sample, on top of the         support net. The plastic cover has a center pin (which is flush         with the outside rim) to ensure that the sample is in the proper         position to establish hydraulic connection. Four other pins, 1         mm shorter in depth, are positioned 1.25-1.5 inches radially         away from the center pin to ensure the sample is flat during the         test. The sample cover rim should not contact the sheet. Close         the top balance window and click “OK”.     -   5. The software re-zeroes the scale and then moves the supply         tube towards the sample. When the supply tube reaches its         destination, which is 0.33 mm below the support net, the valve         opens (i.e., the valve between the reserve tank and the supply         tube), and hydraulic connection is established between the         supply tube and the sample. Data acquisition occurs at a rate of         5 Hz and is started about 0.4 seconds before water contacts the         sample.     -   6. The test runs for at least 20 seconds. After this, the supply         tube pulls away from the sample to break the hydraulic         connection.     -   7. The wet sample is removed from the support net. Residual         water on the support net and cover are dried with a paper towel.     -   8. Repeat until all samples are tested.     -   9. After each test is run, a *.txt file is created (typically         stored in the CRT/data/rate directory) with a file name as typed         at the start of the test. The file contains all the test set-up         parameters, dry sample weight, and cumulative water absorbed (g)         vs. time (sec) data collected from the test.

Calculation of Rate of Uptake

Take the raw data file that includes time and weight data.

First, create a new time column that subtracts 0.4 seconds from the raw time data to adjust the raw time data to correspond to when initiation actually occurs (about 0.4 seconds after data collection begins).

Second, create a column of data that converts the adjusted time data to square root of time data (e.g., using a formula such as SQRT( ) within Excel).

Third, calculate the slope of the weight data vs the square root of time data (e.g., using the SLOPE( ) function within Excel, using the weight data as the y-data and the sqrt(time) data as the x-data, etc.). The slope should be calculated for the data points from 2 to 15 seconds, inclusive (or 1.41 to 3.87 in the sqrt(time) data column).

Calculation of Slope of the Square Root of Time (SST)

The start time of water contact with the sample is estimated to be 0.4 seconds after the start of hydraulic connection is established between the supply tube and the sample (CRT Time). This is because data acquisition begins while the tube is still moving towards the sample and incorporates the small delay in scale response. Thus, “time zero” is actually at 0.4 seconds in CRT Time as recorded in the *.txt file.

The slope of the square root of time (SST) from 2-15 seconds is calculated from the slope of a linear regression line from the square root of time between (and including) 2 to 15 seconds (x-axis) versus the cumulative grams of water absorbed. The units are g/sec^(0.5).

Reporting Results

Report the average slope to the nearest 0.01 g/s^(0.5).

Moist Towel Surface Structure Test Method:

This test method measures the surface topography of a towel surface, both in a dry and moist state, and calculates the % contact area and the median depth of the lowest 10% of the projected measured area, with the test sample under a specified pressure using a smooth and rigid transparent plate with an anti-reflective coating (to minimize and/or eliminate invalid image pixels).

Condition the samples or useable units of product, with wrapper or packaging materials removed, in a room conditioned at 50±2% relative humidity and 23° C.±1° C. (73°±2° F.) for a minimum of two hours prior to testing. Do not test useable units with defects such as wrinkles, tears, holes, effects of tail seal or core adhesive, etc., and when necessary replace with other useable units free of such defects. Test sample dimensions shall be of the size of the usable unit, removed carefully at the perforations if they are present. If perforations are not present, or for samples larger than 8 inches MD by 11 inches CD, cut the sample to a length of approximately 6 inches in the MD and 11 inches in the CD. In this test only the inside surface of the usable unit(s) is analyzed. The inside surface is identified as the surface oriented toward the interior core when wound on a product roll (i.e., the opposite side of the surface visible on the outside roll as presented to a consumer).

The instrument used in this method is a Gocator 3210 Snapshot System (LMI Technologies, Inc., 9200 Glenlyon Parkway, Burnaby, BC V5J 5J8 Canada), or equivalent. This instrument is an optical 3D surface topography measurement system that measures the surface height of a sample using a projected structured light pattern technique. The result of the measurement is a topography map of surface height (z-directional or z-axis) versus displacement in the x-y plane. This particular system has a field of view of approximately 100×154 mm, however the captured images are cropped to 80×130 mm (from the center) prior to analysis. The system has an x-y pixel resolution of 86 microns. The clearance distance from the camera to the testing surface (which is smooth and flat, and perpendicular to the camera view) is 23.5 (+/−0.2) cm—see FIG. 11. Calibration plates can be used to verify that the system is accurate to manufacturer's specifications. The system is set to a Brightness value of 7, and a Dynamic value of 3, in order to most accurately capture the surface topography and minimize non-measured pixels and noise. Other camera settings may be used, with the objective of most accurately measuring the surface topography, while minimizing the number of invalid and non-measurable points.

Test samples are handled only at their corners. The test sample is first weighted on a scale with at least 0.001 gram accuracy, and its dry weight recorded to the nearest 0.01 gram. It is then placed on the testing surface, with its inside face oriented towards the Gocator camera, and centered with respect to the imaging view. A smooth and rigid transparent plate (8×10 inches) is gently placed on top of the test sample, centered with respect to its x-y dimensions. Equal size weights are placed on the four corners of the transparent plate such that they are close to the four corners of the projected imaged area, but do not interfere in any way with the measurement image. The size of each equal sized weight is such that the total weight of transparent plate and the four weights delivers a total pressure of 25 (+/−1) grams per square inch (gsi) to the test sample under the plate. Within 15 seconds of placing the four weights in their proper position, the Gocator system is then initiated to acquire the topography image of the test sample in its ‘dry’ state.

Immediately after saving the Gocator image of the ‘dry’ state image, the weights and plate are removed from the test sample. The test sample is then moved to a smooth, clean countertop surface, with its inside face still up. Using a pipette, 15-30 ml of deionized water is distributed evenly across the entire surface of the test sample until it is visibly apparent that the water has fully wetted the entire test sample, and no unwetted area is observed. The wetting process is to be completed in less than a minute. The wet test sample is then gently picked up by two adjacent corners, so that it hangs freely (dripping may occur), and carefully placed on a sheet of blotter paper (Whatman cellulose blotting paper, grade GB003, cut to dimensions larger than the test sample). The wet test sample must be placed flat on the blotting paper without wrinkles or folds present. A smooth, 304 stainless steel cylindrical rod (density of ˜8 g/cm³), with dimensions of 1.75 inch diameter and 12 inches long, is then rolled over the entire test sample at a speed of 1.5-2.0 inches per second, in the direction of the shorter of the two dimensions of the test sample. If creases or folds are created during the rolling process, and are inside the central area of the sample to be measured (i.e., if they cannot slightly adjusted or avoided in the topography measurement), then the test sample is to be discarded for a new test sample, and the measurement process started over. Otherwise, the moist sample is picked up by two adjacent corners and weighed on the scale to the nearest 0.01 gram (i.e., its moist weight). At this point, the moist test paper towel test sample will have a moisture level between 1.25 and 2.00 grams H₂O per gram of initial dry material.

The moist test sample is then placed flat on the Gocator testing surface (handling it carefully, only touching its corners), with its inside surface pointing towards the Gocator camera, and centered with respect to the imaging view (as close to the same position it was for the ‘dry’ state image). After ensuring that the sample is flat, and no folds or creases are present in the imaging area, the smooth and rigid transparent plate (8×10 inches) is gently placed on top of the test sample, centered with respect to its x-y dimensions. The equal size weights are placed on the four corners of the transparent plate (i.e., the same weights that were used in the dry sample testing) such that they are close to the four corners of the projected imaged area, but do not interfere in any way with the measurement image. Within 15 seconds of placing the four weights in their proper position, the Gocator system is then initiated to acquire the topography image of the test sample in its ‘moist’ state.

At this point, the test sample has both ‘dry’ and ‘moist’ surface topography (3D) images. These are processed using surface texture analysis software such as MountainsMap® (available from Digital Surf, France) or equivalent, as follows: 1) The first step is to crop the image. As stated previously, this particular system has a field of view of approximately 100×154 mm, however the image is cropped to 80×130 mm (from the center). 2) Remove ‘invalid’ and non-measured points. 3) Apply a 3×3 median filter (to reduce effects of noise). 4) Apply an ‘Align’ filter, which subtracts a least squares plane to level the surface (to create an overall average of heights centered at zero). 5) Apply a Gaussian filter (according to ISO 16610-61) with a nesting index (cut-off wavelength) of 25 mm (to flatten out large scale waviness, while preserving finer structure).

From these processed 3D images of the surface, the following parameters are calculated, using software such as MountainsMap® or equivalent: Dry Depth (um), Dry Contact Area (%), Moist Depth (um), and Moist Contact Area (%).

Height measurements are derived from the Areal Material Ratio (Abbott-Firestone) curve described in the ISO 13565-2:1996 standard extrapolated to surfaces. This curve is the cumulative curve of the surface height distribution histogram versus the range of surface heights measured. A material ratio is the ratio, expressed as a percent, of the area corresponding to points with heights equal to or above an intersecting plane passing through the surface at a given height, or cut depth, to the cross-sectional area of the evaluation region (field of view area). For calculating contact area, the height at a material ratio of 2% is first identified. A cut depth of 100 μm below this height is then identified, and the material ratio at this depth is recorded as the “Dry Contact Area” and “Moist Contact Area”, respectively, to the nearest 0.1%.

In order to calculate “Depth” (Dry and Moist, respectively), the depth at the 95% material ratio relative to the mean plane (centered height data) of the specimen surface is identified. This corresponds to a depth equal to the median of the lowest 10% of the projected area (valleys) of the specimen surface and is recorded as the “Dry Depth” and “Moist Depth”, respectively, to the nearest 1 micron (um). These values will be negative as they represent depths below the mean plane of the surface heights having a value of zero.

Three replicate samples are prepared and measured in this way, to produce an average for each of the four parameters: Dry Depth (um), Dry Contact Area (%), Moist Depth (um), and Moist Contact Area (%). Additionally, from these parameters, the difference between the dry and moist depths can be calculated to demonstrate the change in depth from the dry to the moist state.

Plate Stiffness Test Method:

As used herein, the “Plate Stiffness” test is a measure of stiffness of a flat sample as it is deformed downward into a hole beneath the sample. For the test, the sample is modeled as an infinite plate with thickness “t” that resides on a flat surface where it is centered over a hole with radius “R”. A central force “F” applied to the tissue directly over the center of the hole deflects the tissue down into the hole by a distance “w”. For a linear elastic material, the deflection can be predicted by:

$w = {\frac{3F}{4\pi{Et}^{3}}\left( {1 - v} \right)\left( {3 + v} \right)R^{2}}$

where “E” is the effective linear elastic modulus, “v” is the Poisson's ratio, “R” is the radius of the hole, and “t” is the thickness of the tissue, taken as the caliper in millimeters measured on a stack of 5 tissues under a load of about 0.29 psi. Taking Poisson's ratio as 0.1 (the solution is not highly sensitive to this parameter, so the inaccuracy due to the assumed value is likely to be minor), the previous equation can be rewritten for “w” to estimate the effective modulus as a function of the flexibility test results:

$E \approx {\frac{3R^{2}}{4t^{3}}\frac{F}{w}}$

The test results are carried out using an MTS Alliance RT/1, Insight Renew, or similar model testing machine (MTS Systems Corp., Eden Prairie, Minn.), with a 50 newton load cell, and data acquisition rate of at least 25 force points per second. As a stack of five tissue sheets (created without any bending, pressing, or straining) at least 2.5-inches by 2.5 inches, but no more than 5.0 inches by 5.0 inches, oriented in the same direction, sits centered over a hole of radius 15.75 mm on a support plate, a blunt probe of 3.15 mm radius descends at a speed of 20 mm/min. For typical perforated rolled bath tissue, sample preparation consists of removing five (5) connected usable units, and carefully forming a 5 sheet stack, accordion style, by bending only at the perforation lines. When the probe tip descends to 1 mm below the plane of the support plate, the test is terminated. The maximum slope (using least squares regression) in grams of force/mm over any 0.5 mm span during the test is recorded (this maximum slope generally occurs at the end of the stroke). The load cell monitors the applied force and the position of the probe tip relative to the plane of the support plate is also monitored. The peak load is recorded, and “E” is estimated using the above equation.

The Plate Stiffness “S” per unit width can then be calculated as:

$S = \frac{{Et}^{3}}{12}$

and is expressed in units of Newtons*millimeters. The Testworks program uses the following formula to calculate stiffness (or can be calculated manually from the raw data output):

$S = {\left( \frac{F}{w} \right)\left\lbrack \frac{\left( {3 + v} \right)R^{2}}{16\pi} \right\rbrack}$

wherein “F/w” is max slope (force divided by deflection), “v” is Poisson's ratio taken as 0.1, and “R” is the ring radius.

The same sample stack (as used above) is then flipped upside down and retested in the same manner as previously described. This test is run three more times (with different sample stacks). Thus, eight S values are calculated from four 5-sheet stacks of the same sample. The numerical average of these eight S values is reported as Plate Stiffness for the sample.

Stack Compressibility and Resilient Bulk Test Method:

Stack thickness (measured in mils, 0.001 inch) is measured as a function of confining pressure (g/in²) using a Thwing-Albert (14 W. Collings Ave., West Berlin, N.J.) Vantage Compression/Softness Tester (model 1750-2005 or similar) or equivalent instrument, equipped with a 2500 g load cell (force accuracy is +/−0.25% when measuring value is between 10%-100% of load cell capacity, and 0.025% when measuring value is less than 10% of load cell capacity), a 1.128 inch diameter steel pressure foot (one square inch cross sectional area) which is aligned parallel to the steel anvil (2.5 inch diameter). The pressure foot and anvil surfaces must be clean and dust free, particularly when performing the steel-to-steel test. Thwing-Albert software (MAP) controls the motion and data acquisition of the instrument.

The instrument and software are set-up to acquire crosshead position and force data at a rate of 50 points/sec. The crosshead speed (which moves the pressure foot) for testing samples is set to 0.20 inches/min (the steel-to-steel test speed is set to 0.05 inches/min). Crosshead position and force data are recorded between the load cell range of approximately 5 and 1500 grams during compression. The crosshead is programmed to stop immediately after surpassing 1500 grams, record the thickness at this pressure (termed T_(max)), and immediately reverse direction at the same speed as performed in compression. Data is collected during this decompression portion of the test (also termed recovery) between approximately 1500 and 5 grams. Since the foot area is one square inch, the force data recorded corresponds to pressure in units of g/in². The MAP software is programmed to the select 15 crosshead position values (for both compression and recovery) at specific pressure trap points of 10, 25, 50, 75, 100, 125, 150, 200, 300, 400, 500, 600, 750, 1000, and 1250 g/in² (i.e., recording the crosshead position of very next acquired data point after the each pressure point trap is surpassed). In addition to these 30 collected trap points, T_(max) is also recorded, which is the thickness at the maximum pressure applied during the test (approximately 1500 g/in²).

Since the overall test system, including the load cell, is not perfectly rigid, a steel-to-steel test is performed (i.e., nothing in between the pressure foot and anvil) at least twice for each batch of testing, to obtain an average set of steel-to-steel crosshead positions at each of the 31 trap points described above. This steel-to-steel crosshead position data is subtracted from the corresponding crosshead position data at each trap point for each tested stacked sample, thereby resulting in the stack thickness (mils) at each pressure trap point during the compression, maximum pressure, and recovery portions of the test.

StackT(trap)=StackCP(trap)−SteelCP(trap)

Where:

-   -   trap=trap point pressure at either compression, recovery, or max     -   StackT=Thickness of Stack (at trap pressure)     -   StackCP=Crosshead position of Stack in test (at trap pressure)     -   SteelCP=Crosshead position of steel-to-steel test (at trap         pressure)

A stack of five (5) usable units thick is prepared for testing as follows. The minimum usable unit size is 2.5 inch by 2.5 inch; however a larger sheet size is preferable for testing, since it allows for easier handling without touching the central region where compression testing takes place. For typical perforated rolled bath tissue, this consists of removing five (5) sets of 3 connected usable units. In this case, testing is performed on the middle usable unit, and the outer 2 usable units are used for handling while removing from the roll and stacking. For other product formats, it is advisable, when possible, to create a test sheet size (each one usable unit thick) that is large enough such that the inner testing region of the created 5 usable unit thick stack is never physically touched, stretched, or strained, but with dimensions that do not exceed 14 inches by 6 inches.

The 5 sheets (one usable unit thick each) of the same approximate dimensions, are placed one on top the other, with their MD aligned in the same direction, their outer face all pointing in the same direction, and their edges aligned +/−3 mm of each other. The central portion of the stack, where compression testing will take place, is never to be physically touched, stretched, and/or strained (this includes never to ‘smooth out’ the surface with a hand or other apparatus prior to testing).

The 5 sheet stack is placed on the anvil, positioning it such that the pressure foot will contact the central region of the stack (for the first compression test) in a physically untouched spot, leaving space for a subsequent (second) compression test, also in the central region of the stack, but separated by ¼ inch or more from the first compression test, such that both tests are in untouched, and separated spots in the central region of the stack. From these two tests, an average crosshead position of the stack at each trap pressure (i.e., StackCP(trap)) is calculated for compression, maximum pressure, and recovery portions of the tests. Then, using the average steel-to-steel crosshead trap points (i.e., SteelCP(trap)), the average stack thickness at each trap (i.e., StackT(trap) is calculated (mils).

Stack Compressibility is defined here as the absolute value of the linear slope of the stack thickness (mils) as a function of the log(10) of the confining pressure (grams/in²), by using the 15 compression trap points discussed previously (i.e., compression from 10 to 1250 g/in²), in a least squares regression. The units for Stack Compressibility are [mils/(log(g/in²))], and is reported to the nearest 0.1 [mils/(log(g/in²))].

Resilient Bulk is calculated from the stack weight per unit area and the sum of 8 StackT(trap) thickness values from the maximum pressure and recovery portion of the tests: i.e., at maximum pressure (T_(max)) and recovery trap points at R1250, R1000, R750, R500, R300, R100, and R10 g/in² (a prefix of “R” denotes these traps come from recovery portion of the test). Stack weight per unit area is measured from the same region of the stack contacted by the compression foot, after the compression testing is complete, by cutting a 3.50 inch square (typically) with a precision die cutter, and weighing on a calibrated 3-place balance, to the nearest 0.001 gram. The weight of the precisely cut stack, along with the StackT(trap) data at each required trap pressure (each point being an average from the two compression/recovery tests discussed previously), are used in the following equation to calculate Resilient Bulk, reported in units of cm³/g, to the nearest 0.1 cm³/g.

${{Resilient}{Bulk}} = \frac{{{SUM}\left( {{StackT}\left( {T_{\max},{R1250},{R1000},{R750},{R500},{R300},{R100},{R10}} \right)} \right)}*0.00254}{M/A}$

Where:

-   -   StackT=Thickness of Stack (at trap pressures of T_(max) and         recovery pressures listed above), (mils)     -   M=weight of precisely cut stack, (grams)     -   A=area of the precisely cut stack, (cm²)

Wet Burst Test Method:

“Wet Burst Strength” as used herein is a measure of the ability of a fibrous structure and/or a fibrous structure product incorporating a fibrous structure to absorb energy, when wet and subjected to deformation normal to the plane of the fibrous structure and/or fibrous structure product. The Wet Burst Test is run according to ISO 12625-9:2005, except for any deviations or modifications described below.

Wet burst strength may be measured using a Thwing-Albert Burst Tester Cat. No. 177 equipped with a 2000 g load cell commercially available from Thwing-Albert Instrument Company, Philadelphia, Pa., or an equivalent instrument.

Wet burst strength is measured by preparing four (4) multi-ply fibrous structure product samples for testing. First, condition the samples for two (2) hours at a temperature of 73° F.±2° F. (23° C.±1° C.) and a relative humidity of 50% (±2%). Take one sample and horizontally dip the center of the sample into a pan filled with about 25 mm of room temperature distilled water. Leave the sample in the water four (4) (±0.5) seconds. Remove and drain for three (3) (±0.5) seconds holding the sample vertically so the water runs off in the cross-machine direction. Proceed with the test immediately after the drain step.

Place the wet sample on the lower ring of the sample holding device of the Burst Tester with the outer surface of the sample facing up so that the wet part of the sample completely covers the open surface of the sample holding ring. If wrinkles are present, discard the samples and repeat with a new sample. After the sample is properly in place on the lower sample holding ring, turn the switch that lowers the upper ring on the Burst Tester. The sample to be tested is now securely gripped in the sample holding unit. Start the burst test immediately at this point by pressing the start button on the Burst Tester. A plunger will begin to rise (or lower) toward the wet surface of the sample. At the point when the sample tears or ruptures, report the maximum reading. The plunger will automatically reverse and return to its original starting position. Repeat this procedure on three (3) more samples for a total of four (4) tests, i.e., four (4) replicates. Report the results as an average of the four (4) replicates, to the nearest gram.

Wet Tensile Test Method:

Wet Elongation, Tensile Strength, and TEA are measured on a constant rate of extension tensile tester with computer interface (a suitable instrument is the EJA Vantage from the Thwing-Albert Instrument Co. West Berlin, N.J.) using a load cell for which the forces measured are within 10% to 90% of the limit of the load cell. Both the movable (upper) and stationary (lower) pneumatic jaws are fitted with smooth stainless steel faced grips, with a design suitable for testing 1 inch wide sheet material (Thwing-Albert item #733GC). An air pressure of about 60 psi is supplied to the jaws.

Eight usable units of fibrous structures are divided into two stacks of four usable units each. The usable units in each stack are consistently oriented with respect to machine direction (MD) and cross direction (CD). One of the stacks is designated for testing in the MD and the other for CD. Using a one inch precision cutter (Thwing Albert) take a CD stack and cut one, 1.00 in ±0.01 in wide by at least 3.0 in long stack of strips (long dimension in CD). In like fashion cut the remaining stack in the MD (strip long dimension in MD), to give a total of 8 specimens, four CD and four MD strips. Each strip to be tested is one usable unit thick, and will be treated as a unitary specimen for testing.

Program the tensile tester to perform an extension test (described below), collecting force and extension data at an acquisition rate of 100 Hz as the crosshead raises at a rate of 2.00 in/min (10.16 cm/min) until the specimen breaks. The break sensitivity is set to 50%, i.e., the test is terminated when the measured force drops below 50% of the maximum peak force, after which the crosshead is returned to its original position.

Set the gage length to 2.00 inches. Zero the crosshead and load cell. Insert the specimen into the upper and lower open grips such that at least 0.5 inches of specimen length is contained each grip. Align the specimen vertically within the upper and lower jaws, then close the upper grip. Verify the specimen is hanging freely and aligned with the lower grip, then close the lower grip. Initiate the first portion of the test, which pulls the specimen at a rate of 0.5 in/min, then stops immediately after a load of 10 grams is achieved. Using a pipet, thoroughly wet the specimen with DI water to the point where excess water can be seen pooling on the top of the lower closed grip Immediately after achieving this wetting status, initiate the second portion of the test, which pulls the wetted strip at 2.0 in/min until break status is achieved. Repeat testing in like fashion for all four CD and four MD specimens.

Program the software to calculate the following from the constructed force (g) verses extension (in) curve:

Wet Tensile Strength (g/in) is the maximum peak force (g) divided by the specimen width (1 in), and reported as g/in to the nearest 0.1 Win.

Adjusted Gage Length (in) is calculated as the extension measured (from original 2.00 inch gage length) at 3 g of force during the test following the wetting of the specimen (or the next data point after 3 g force) added to the original gage length (in). If the load does not fall below 3 g force during the wetting procedure, then the adjusted gage length will be the extension measured at the point the test is resumed following wetting added to the original gage length (in).

Wet Peak Elongation (%) is calculated as the additional extension (in) from the Adjusted Gage Length (in) at the maximum peak force point (more specifically, at the last maximum peak force point, if there is more than one) divided by the Adjusted Gage Length (in) multiplied by 100 and reported as % to the nearest 0.1%.

Wet Peak Tensile Energy Absorption (TEA, g*in/in²) is calculated as the area under the force curve (g*in²) integrated from zero extension (i.e., the Adjusted Gage Length) to the extension at the maximum peak force elongation point (more specifically, at the last maximum peak force point, if there is more than one) (in), divided by the product of the adjusted Gage Length (in) and specimen width (in). This is reported as g*in/in² to the nearest 0.01 g*in/in².

The Wet Tensile Strength (g/in), Wet Peak Elongation (%), Wet Peak TEA (g*in/in² are calculated for the four CD specimens and the four MD specimens. Calculate an average for each parameter separately for the CD and MD specimens.

Calculations

Geometric Mean Initial Wet Tensile Strength=Square Root of [MD Wet Tensile Strength

(g/in)×CD Wet Tensile Strength (g/in)]

Geometric Mean Wet Peak Elongation=Square Root of [MD Wet Peak Elongation (%)×CD

Wet Peak Elongation (%)]

Geometric Mean Wet Peak TEA=Square Root of [MD Wet Peak TEA (g*in/in²)×CD Wet

Peak TEA (g*in/in²)]

Total Wet Tensile (TWT)=MD Wet Tensile Strength (g/in)+CD Wet Tensile Strength (g/in)

Total Wet Peak TEA=MD Wet Peak TEA (g*in/in²)+CD Wet Peak TEA (g*in/in²)

Wet Tensile Ratio=MD Wet Peak Tensile Strength (g/in)/CD Wet Peak Tensile Strength

(g/in)

Wet Tensile Geometric Mean (GM) Modulus=Square Root of [MD Modulus (at 38 g/cm)×

CD Modulus (at 38 g/cm)]

Dry Elongation, Tensile Strength, TEA and Modulus Test Methods:

Remove five (5) strips of four (4) usable units (also referred to as sheets) of fibrous structures and stack one on top of the other to form a long stack with the perforations between the sheets coincident. Identify sheets 1 and 3 for machine direction tensile measurements and sheets 2 and 4 for cross direction tensile measurements. Next, cut through the perforation line using a paper cutter (JDC-1-10 or MC-1-12 with safely shield from Thwing-Albert Instrument Co. of Philadelphia, Pa.) to make 4 separate stacks. Make sure stacks 1 and 3 are still identified for machine direction testing and stacks 2 and 4 are identified for cross direction testing.

Cut two 1 inch (2.54 cm) wide strips in the machine direction from stacks 1 and 3. Cut two 1 inch (2.54 cm) wide strips in the cross direction from stacks 2 and 4. There are now four 1 inch (2.54 cm) wide strips for machine direction tensile testing and four 1 inch (2.54 cm) wide strips for cross direction tensile testing. For these finished product samples, all eight 1 inch (2.54 cm) wide strips are five usable units (sheets) thick.

For the actual measurement of the elongation, tensile strength, TEA and modulus, use a Thwing-Albert Intelect II Standard Tensile Tester (Thwing-Albert Instrument Co. of Philadelphia, Pa.). Insert the flat face clamps into the unit and calibrate the tester according to the instructions given in the operation manual of the Thwing-Albert Intelect II. Set the instrument crosshead speed to 4.00 in/min (10.16 cm/min) and the 1st and 2nd gauge lengths to 2.00 inches (5.08 cm). The break sensitivity is set to 20.0 grams and the sample width is set to 1.00 inch (2.54 cm) and the sample thickness is set to 0.3937 inch (1 cm). The energy units are set to TEA and the tangent modulus (Modulus) trap setting is set to 38.1 g.

Take one of the fibrous structure sample strips and place one end of it in one clamp of the tensile tester. Place the other end of the fibrous structure sample strip in the other clamp. Make sure the long dimension of the fibrous structure sample strip is running parallel to the sides of the tensile tester. Also make sure the fibrous structure sample strips are not overhanging Lo the either side of the two clamps. In addition, the pressure of each of the clamps must be in full contact with the fibrous structure sample strip.

After inserting the fibrous structure sample strip into the two clamps, the instrument tension can be monitored. If it shows a value of 5 grams or more, the fibrous structure sample strip is too taut. Conversely, if a period of 2-3 seconds passes after starting the test before any value is recorded, the fibrous structure sample strip is too slack.

Start the tensile tester as described in the tensile tester instrument manual. The test is complete after the crosshead automatically returns to its initial starting position. When the test is complete, read and record the following with units of measure:

-   -   Peak Load Tensile (Tensile Strength) (g/in)     -   Peak Elongation (Elongation) (%)     -   Peak TEA (TEA) (in-g/in²)     -   Tangent Modulus (Modulus) (at 15 g/cm)

Test each of the samples in the same manner, recording the above measured values from each test.

Calculations:

Geometric Mean (GM) Dry Elongation=Square Root of [MD Elongation (%)×CD Elongation (%)]

Total Dry Tensile (TDT)=Peak Load MD Tensile (g/in)+Peak Load CD Tensile (g/in)

Dry Tensile Ratio=Peak Load MD Tensile (g/in)/Peak Load CD Tensile (g/in)

Geometric Mean (GM) Dry Tensile=[Square Root of (Peak Load MD Tensile (g/in)×Peak Load

CD Tensile (g/in))]

Dry TEA=MD TEA (in-g/in²)+CD TEA (in-g/in²)

Geometric Mean (GM) Dry TEA=Square Root of [MD TEA (in-g/in²)×CD TEA (in-g/in²)]

Dry Modulus=MD Modulus (at 15 g/cm)+CD Modulus (at 15 g/cm)

Geometric Mean (GM) Dry Modulus=Square Root of [MD Modulus (at 15 g/cm)×CD Modulus

(at 15 g/cm)]

Flexural Rigidity Test Method:

This test is performed on 1 inch×6 inch (2.54 cm×15.24 cm) strips of a fibrous structure sample. A Cantilever Bending Tester such as described in ASTM Standard D 1388 (Model 5010, Instrument Marketing Services, Fairfield, N.J.) is used and operated at a ramp angle of 41.5±0.5° and a sample slide speed of 0.5±0.2 in/second (1.3±0.5 cm/second). A minimum of n=16 tests are performed on each sample from n=8 sample strips.

No fibrous structure sample which is creased, bent, folded, perforated, or in any other way weakened should ever be tested using this test. A non-creased, non-bent, non-folded, non-perforated, and non-weakened in any other way fibrous structure sample should be used for testing under this test.

From one fibrous structure sample of about 4 inch×6 inch (10.16 cm×15.24 cm), carefully cut using a 1 inch (2.54 cm) JDC Cutter (available from Thwing-Albert Instrument Company, Philadelphia, Pa.) four (4) 1 inch (2.54 cm) wide by 6 inch (15.24 cm) long strips of the fibrous structure in the MD direction. From a second fibrous structure sample from the same sample set, carefully cut four (4) 1 inch (2.54 cm) wide by 6 inch (15.24 cm) long strips of the fibrous structure in the CD direction. It is important that the cut be exactly perpendicular to the long dimension of the strip. In cutting non-laminated two-ply fibrous structure strips, the strips should be cut individually. The strip should also be free of wrinkles or excessive mechanical manipulation which can impact flexibility. Mark the direction very lightly on one end of the strip, keeping the same surface of the sample up for all strips. Later, the strips will be turned over for testing, thus it is important that one surface of the strip be clearly identified, however, it makes no difference which surface of the sample is designated as the upper surface.

Using other portions of the fibrous structure (not the cut strips), determine the basis weight of the fibrous structure sample in lbs/3000 ft² and the caliper of the fibrous structure in mils (thousandths of an inch) using the standard procedures disclosed herein. Place the Cantilever Bending Tester level on a bench or table that is relatively free of vibration, excessive heat and most importantly air drafts. Adjust the platform of the Tester to horizontal as indicated by the leveling bubble and verify that the ramp angle is at 41.5±0.5°. Remove the sample slide bar from the top of the platform of the Tester. Place one of the strips on the horizontal platform using care to align the strip parallel with the movable sample slide. Align the strip exactly even with the vertical edge of the Tester wherein the angular ramp is attached or where the zero mark line is scribed on the Tester. Carefully place the sample slide bar back on top of the sample strip in the Tester. The sample slide bar must be carefully placed so that the strip is not wrinkled or moved from its initial position.

Move the strip and movable sample slide at a rate of approximately 0.5±0.2 in/second (1.3±0.5 cm/second) toward the end of the Tester to which the angular ramp is attached. This can be accomplished with either a manual or automatic Tester. Ensure that no slippage between the strip and movable sample slide occurs. As the sample slide bar and strip project over the edge of the Tester, the strip will begin to bend, or drape downward. Stop moving the sample slide bar the instant the leading edge of the strip falls level with the ramp edge. Read and record the overhang length from the linear scale to the nearest 0.5 mm Record the distance the sample slide bar has moved in cm as overhang length. This test sequence is performed a total of eight (8) times for each fibrous structure in each direction (MD and CD). The first four strips are tested with the upper surface as the fibrous structure was cut facing up. The last four strips are inverted so that the upper surface as the fibrous structure was cut is facing down as the strip is placed on the horizontal platform of the Tester.

The average overhang length is determined by averaging the sixteen (16) readings obtained on a fibrous structure.

${{Overhang}{Length}{}{MD}} = \frac{{Sum}{of}8{MD}{readings}}{8}$ ${{Overhang}{Length}{}{CD}} = \frac{{Sum}{of}8{CD}{readings}}{8}$ ${{Overhang}{Length}{}{Total}} = \frac{{Sum}{of}{all}{}16{readings}}{16}$ ${{Bend}{Length}{}{MD}} = \frac{{Overhang}{Length}{MD}}{2}$ ${{Bend}{Length}{}{CD}} = \frac{{Overhang}{Length}{CD}}{2}$ ${{Bend}{Length}{}{Total}} = \frac{{Overhang}{Length}{Total}}{2}$ FlexuralRigidity = 0.1629 × W × C³

wherein W is the basis weight of the fibrous structure in lbs/3000 ft²; C is the bending length (MD or CD or Total) in cm; and the constant 0.1629 is used to convert the basis weight from English to metric units. The results are expressed in mg-cm.

GM Flexural Rigidity=Square root of (MD Flexural Rigidity×CD Flexural Rigidity)

Slip Stick Coefficient of Friction Test Method:

Background

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Of particular interest here, ‘dry’ friction resists relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction between non-moving surfaces, and kinetic friction between moving surfaces. “Slip Stick”, as applied here, is the term used to describe the dynamic variation in kinetic friction.

Friction is not itself a fundamental force but arises from fundamental electromagnetic forces between the charged particles constituting the two contacting surfaces. Textured surfaces also involve mechanical interactions, as is the case when sandpaper drags against a fibrous substrate. The complexity of these interactions makes the calculation of friction from first principles impossible and necessitates the use of empirical methods for analysis and the development of theory. As such, a specific sled material and test method was identified, and has shown correlation to human perception of surface feel.

This Slip Stick Coefficient of Friction Test Method measures the interaction of a diamond file (120-140 grit) against a surface of a test sample, in this case a fibrous structure and/or sanitary tissue product, at a pressure of about 32 g/in² as shown in FIGS. 12-14. The friction measurements are highly dependent on the exactness of the sled material surface properties, and since each sled has no ‘standard’ reference, sled-to-sled surface property variation is accounted for by testing a test sample with multiple sleds, according to the equipment and procedure described below.

Equipment and Set-up

A Thwing-Albert (14 W. Collings Ave., West Berlin, N.J.) friction/peel test instrument (model 225-1) or equivalent if no longer available, is used, equipped with data acquisition software and a calibrated 2000 gram load cell that moves horizontally across the platform. Attached to the load cell is a small metal fitting (defined here as the “load cell arm”) which has a small hole near its end, such that a sled string can be attached (for this method, however, no string will be used). Into this load cell arm hole, insert a cap screw (¾ inch #8-32) by partially screwing it into the opening, so that it is rigid (not loose) and pointing vertically, perpendicular to the load cell arm.

After turning instrument on, set instrument test speed to 2 inches/min, test time to 10 seconds, and wait at least 5 minutes for instrument to warm up before re-zeroing the load cell (with nothing touching it) and testing. Force data from the load cell is acquired at a rate of 52 points per second, reported to the nearest 0.1 gram force. Press the ‘Return’ button to move crosshead 201 to its home position.

A smooth surfaced metal test platform 200, with dimensions of 5 inches by 4 inches by ¾ inch thick, is placed on top of the test instrument platen surface, on the left hand side of the load cell 203, with one of its 4 inch by ¾ inch sides facing towards the load cell 203, positioned 1.125 inches d from the left most tip of the load cell arm 202 as shown in FIGS. 12 and 14.

Sixteen test sleds 204 are required to perform this test (32 different sled surface faces). Each is made using a dual sided, wide faced diamond file 206 (25 mm×25 mm, 120/140 grit, 1.2 mm thick, McMaster-Carr part number 8142A14) with 2 flat metal washers 208 (approximately 11/16th inch outer diameter and about 11/32nd inch inner diameter). The combined weight of the diamond file 206 and 2 washers 208 is 11.7 grams+/−0.2 grams (choose different washers until weight is within this range). Using a metal bonding adhesive (Loctite 430, or similar), adhere the 2 washers 208 to the c-shaped end 210 of the diamond file 206 (one each on either face), aligned and positioned such that the opening 212 is large enough for the cap screw 214 to easily fit into, and to make the total length of sled 204 to approximately 3 inches long. Clean sled 204 by dipping it, diamond face end 216 only, into an acetone bath, while at the same time gently brushing with soft bristled toothbrush 3-6 times on both sides of the diamond file 206. Remove from acetone and pat dry each side with Kimwipe tissue (do not rub tissue on diamond surface, since this could break tissue pieces onto sled surface). Wait at least 15 minutes before using sled 204 in a test. Label each side of the sled 204 (on the arm or washer, not on the diamond face) with a unique identifier (i.e., the first sled is labeled “1 a” on one side, and “1 b” on its other side). When all 16 sleds 204 are created and labeled, there are then 32 different diamond face surfaces for available for testing, labeled 1 a and 1 b through 16 a and 16 b. These sleds 204 must be treated as fragile (particularly the diamond surfaces) and handled carefully; thus, they are stored in a slide box holder, or similar protective container.

Sample Prep

If sample to be tested is bath tissue, in perforated roll form, then gently remove 8 sets of 2 connected sheets from the roll, touching only the corners (not the regions where the test sled will contact). Use scissors or other sample cutter if needed. If sample is in another form, cut 8 sets of sample approximately 8 inches long in the MD, by approximately 4 inches long in the CD, one usable unit thick each. Make note and/or a mark that differentiates both face sides of each sample (e.g., fabric side or wire side, top or bottom, etc.). When sample prep is complete, there are 8 sheets prepared with appropriate marking that differentiates one side from the other. These will be referred to hereinafter as: sheets #1 through #8, each with a top side and a bottom side.

Test Operation

Press the ‘Return’ button to ensure crosshead 201 is in its home position.

Without touching test area of sample, place sheet #1 218 on test platform 200, top side facing up, aligning one of the sheet's CD edges (i.e. edge that is parallel to the CD) along the platform 218 edge closest to the load cell 202 (+/−1 mm). This first test (pull), of 32 total, will be in the MD direction on the top side of the sheet 218. Place a brass bar weight or equivalent 220 (1 inch diameter, 3.75 inches long) on the sheet 218, near its center, aligned perpendicular to the sled pull direction, to prevent sheet 218 from moving during the test. Place test sled “1 a” 204 over cap screw head 214 (i.e., sled washer opening 212 over cap screw head 214, and sled side 1 a is facing down) such that the diamond file 206 surface is laying flat and parallel on the sheet 218 surface and the cap screw 214 is touching the inside edge of the washers 208.

Gently place a cylindrically shaped brass 20 gram (+/−0.01 grams) weight 222 on top of the sled 204, with its edge aligned and centered with the sled's back end. Initiate the sled movement m and data acquisition by pressing the ‘Test’ button on the instrument. The test set up is shown in FIG. 14. The computer collects the force (grams) data and, after approximately 10 seconds of test time, this first of 32 test pulls of the overall test is complete.

If the test pull was set-up correctly, the diamond file 206 face (25 mm by 25 mm square) stays in contact with the sheet 218 during the entire 10 second test time (i.e., does not overhang over the sheet 218 or test platform 200 edge). Also, if at any time during the test the sheet 218 moves, the test is invalid, and must be rerun on another untouched portion of the sheet 218, using a heavier brass bar weight or equivalent 220 to hold sheet 218 down. If the sheet 218 rips or tears, rerun the test on another untouched portion of the sheet 218 (or create a new sheet 218 from the sample). If it rips again, then replace the sled 204 with a different one (giving it the same sled name as the one it replaced). These statements apply to all 32 test pulls.

For the second of 32 test pulls (also an MD pull, but in the opposite direction on the sheet), first remove the 20 gram weight 222, the sled 204, and the brass bar weight or equivalent 220 from the sheet 218. Press the ‘Return’ button on the instrument to reset the crosshead 201 to its home position. Rotate the sheet 218 180° (with top side still facing up), and replace the brass bar weight or equivalent 220 onto the sheet 218 (in the same position described previously). Place test sled “1 b” 204 over the cap screw head 214 (i.e., sled washer opening 212 over cap screw head 214, and sled side 1 b is facing down) and the 20 gram weight 222 on the sled 204, in the same manner as described previously. Press the ‘Test’ button to collect the data for the second test pull.

The third test pull will be in the CD direction. After removing the sled 204, weights 220, 222, and returning the crosshead 201, the sheet 218 is rotated 90° from its previous position (with top side still facing up), and positioned so that its MD edge is aligned with the test platform 200 edge (+/−1 mm). Position the sheet 218 such that the sled 204 will not touch any perforation, if present, or touch the area where the brass bar weight or equivalent 220 rested in previous test pulls. Place the brass bar weight or equivalent 220 onto the sheet 218 near its center, aligned perpendicular to the sled pull direction m. Place test sled “2 a” 204 over the cap screw head 214 (i.e., sled washer opening 212 over cap screw head 214, and sled side 2 a is facing down) and the 20 gram weight 222 on the sled 204, in the same manner as described previously. Press the ‘Test’ button to collect the data for the third test pull.

The fourth test pull will also be in the CD, but in the opposite direction and on the opposite half section of the sheet 218. After removing the sled 204, weights 220, 222, and returning the crosshead 201, the sheet 218 is rotated 180° from its previous position (with top side still facing up), and positioned so that its MD edge is again aligned with the test platform 200 edge (+/−1 mm). Position the sheet 218 such that the sled 204 will not touch any perforation, if present, or touch the area where the brass bar weight or equivalent 220 rested in previous test pulls. Place the brass bar weight or equivalent 220 onto the sheet 218 near its center, aligned perpendicular to the sled pull direction m. Place test sled “2 b” 204 over the cap screw head 214 (i.e., sled washer opening 212 over cap screw head 214, and sled side 2 b is facing down) and the 20 gram weight 222 on the sled 204, in the same manner as described previously. Press the ‘Test’ button to collect the data for the fourth test pull.

After the fourth test pull is complete, remove the sled 204, weights 220, 222, and return the crosshead 201 to the home position. Sheet #1 218 is discarded.

Test pulls 5-8 are performed in the same manner as 1-4, except that sheet #2 218 has its bottom side now facing upward, and sleds 3 a, 3 b, 4 a, and 4 b are used.

Test pulls 9-12 are performed in the same manner as 1-4, except that sheet #3 218 has its top side facing upward, and sleds 5 a, 5 b, 6 a, and 6 b are used.

Test pulls 13-16 are performed in the same manner as 1-4, except that sheet #4 218 has its bottom side facing upward, and sleds 7 a, 7 b, 8 a, and 8 b are used.

Test pulls 17-20 are performed in the same manner as 1-4, except that sheet #5 218 has its top side facing upward, and sleds 9 a, 9 b, 10 a, and 10 b are used.

Test pulls 21-24 are performed in the same manner as 1-4, except that sheet #6 218 has its bottom side facing upward, and sleds 11 a, 11 b, 12 a, and 12 b are used.

Test pulls 25-28 are performed in the same manner as 1-4, except that sheet #7 218 has its top side facing upward, and sleds 13 a, 13 b, 14 a, and 14 b are used.

Test pulls 29-32 are performed in the same manner as 1-4, except that sheet #8 218 has its bottom side facing upward, and sleds 15 a, 15 b, 16 a, and 16 b are used.

Calculations and Results

The collected force data (grams) is used to calculate Slip Stick COF for each of the 32 test pulls, and subsequently the overall average Slip Stick COF for the sample being tested. In order to calculate Slip Stick COF for each test pull, the following calculations are made. First, the standard deviation is calculated for the force data centered on 131st data point (which is 2.5 seconds after the start of the test)+/−26 data points (i.e., the 53 data points that cover the range from 2.0 to 3.0 seconds). This standard deviation calculation is repeated for each subsequent data point, and stopped after the 493rd point (about 9.5 sec). The numerical average of these 363 standard deviation values is then divided by the sled weight (31.7 g) and multiplied by 10,000 to generate the Slip Stick COF*10,000 for each test pull. This calculation is repeated for all 32 test pulls. The numerical average of these 32 Slip Stick COF*10,000 values is the reported value of the Slip Stick COF*10,000 for the sample. For simplicity, it is referred to as just Slip Stick COF, or more simply as Slip Stick, without units (dimensionless), and is reported to the nearest 1.0.

Outliers and Noise

It is not uncommon, with this described method, to observe about one out of the 32 test pulls to exhibit force data with a harmonic wave of vibrations superimposed upon it. For whatever reason, the pulled sled periodically gets into a relatively high frequency, oscillating ‘shaking’ mode, which can be seen in graphed force vs. time. The sine wave-like noise was found to have a frequency of about 10 sec-1 and amplitude in the 3-5 grams force range. This adds a bias to the true Slip Stick result for that test; thus, it is appropriate for this test pull be treated as an outlier, the data removed, and replaced with a new test of that same scenario (e.g., CD top face) and sled number (e.g. 3 a).

To get an estimate of the overall measurement noise, ‘blanks’ were run on the test instrument without any touching the load cell (i.e., no sled). The average force from these tests is zero grams, but the calculated Slip Stick COF was 66. Thus, it is speculated that, for this instrument measurement system, this value represents that absolute lower limit for Slip Stick COF.

In the interests of brevity and conciseness, any ranges of values set forth in this specification are to be construed as written description support for Claims reciting any sub-ranges having endpoints which are whole number values within the specified range in question. By way of a hypothetical illustrative example, a disclosure in this specification of a range of 1-5 shall be considered to support Claims to any of the following sub-ranges: 1-4; 1-3; 1-2; 2-5; 2-4; 2-3; 3-5; 3-4; and 4-5.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. 

What is claimed is:
 1. A fibrous structure comprising a surface comprising a plurality of first pillows wherein at least a portion of the plurality of first pillows are at least partially bounded by at least a portion of a second pillow different from the plurality of first pillows, wherein the portion of the second pillow exhibits a maximum width that is less than the maximum dimension of one or more of the plurality of first pillows.
 2. The fibrous structure according to claim 1 wherein the portion of the plurality of first pillows are fully bound by the portion of the second pillow.
 3. The fibrous structure according to claim 1 wherein the second pillow forms a continuous network pillow.
 4. The fibrous structure according to claim 1 wherein at least one of the plurality of first pillows exhibits a cell size of at least 16 cell/in².
 5. The fibrous structure according to claim 1 wherein at least one of the plurality of first pillows protrudes from the surface by greater than 0.025 inches.
 6. The fibrous structure according to claim 1 wherein the plurality of first pillows are separated from the second pillow by one or more knuckles.
 7. The fibrous structure according to claim 6 wherein at least a portion of the knuckle is a continuous knuckle.
 8. The fibrous structure according to claim 7 wherein the portion of the plurality of first pillows are dispersed throughout the continuous knuckle.
 9. The fibrous structure according to claim 1 wherein the fibrous structure comprises pulp fibers.
 10. The fibrous structure according to claim 9 wherein the pulp fibers comprise wood pulp fibers.
 11. The fibrous structure according to claim 9 wherein the pulp fibers comprise non-wood pulp fibers.
 12. The fibrous structure according to claim 1 wherein the fibrous structure comprises water-insensitive fibers.
 13. The fibrous structure according to claim 1 wherein the fibrous structure comprises synthetic fibers.
 14. The fibrous structure according to claim 13 wherein the synthetic fibers comprise non-thermoplastic synthetic fibers.
 15. The fibrous structure according to claim 13 wherein the synthetic fibers comprise regenerated cellulose fibers.
 16. The fibrous structure according to claim 15 wherein the regenerated cellulose fibers are selected from the group consisting of: rayon fibers, viscose fibers, and mixtures thereof.
 17. The fibrous structure according to claim 13 wherein the plurality of first pillows comprise synthetic fibers.
 18. The fibrous structure according to claim 1 wherein the fibrous structure exhibits a TS7 of less than 20 dB V² rms as measured according to the Emtec Test Method.
 19. The fibrous structure according to claim 1 wherein the plurality of first pillows comprise greater than 80% of their original height after wetting.
 20. The fibrous structure according to claim 1 wherein the fibrous structure is dry-to-the-touch after wetting. 